@MangaField
I’m getting the indication that you only watched the Golden age movies(they hollowed out many of the relationships) and then read the manga(even then I still wonder if you just didn’t read it well), so I'll respond with what I got from reading the manga. Guts didn’t start his trust issues because of the rape, it only started after Gambino told him that he was the one who sold him as a child prostitute, told him he should have died and he was chased out of his only home, it wasn’t only one thing it was all these series of event and they were expertly done because of the fact that Gambino is Guts’ only father who taught him all he knew and Guts, always wanted to prove himself to him when Guts killed Gambino, it wasn’t rage, he just lunged his sword in sadness(not only has he stated this in the manga but his expression in the manga is one of sadness). Next, you say that Griffith and Casca have little characterization but that isn’t true, I’ll explain Griffith then Casca but I’ll Segway to the war scenes in Berserk. You say the Golden Age is a worse kingdom but first of all, I think the Golden Age is actually better than Kingdom(but this is my personal preference) and Kingdom is a military drama while Berserk’s Golden Age was a character drama with a militaristic backdrop and there are only three actual military battles with armies and they were the battle for Doldrey, the battle at the end of volume 4 and beginning of volume 5 and maybe the battle with the black rams in volume 5(but this isn’t really an army battle because it end too quickly). Anyway, I’ll start with the volume 4-5, it had strategy didn’t you read it clearly, Griffith’s plan was that the hawks will ride through the centre of the enemy camp from the centre and set fire to the enemy rations and supplies while Guts will be the rear guard, they moved in the river which had a swift current and it was also a day of strong wind and Griffith chose the rear for attack because it was windward and it will fan the flames. Against the black rams, Guts and Casca’s armies were meant to flank the enemy(black rams) and form a containment around the enemy for Griffith main force to charge into but Guts charged in to kill the general so Griffith went with it and attacked the enemy using an arrow formation(check the manga). You say Miura tells not show not this is strictly untrue, during Doldrey his plan was for the Guts’ raiders to charge to the enemy line and retreat back to the HQ and the enemy will chase them because of name recognition, the fact that the purple rhinos had an advantage of numbers and the fact that the hawk had a river to their back and seemed like sitting ducks. Griffith plan was for Guts as the strongest member to face Boscogne the general of the purple rhinos and as the rhinos come to attack them, Casca’s leads her force into Doldrey using a sandstorm to cover her tracks, the army is in disarray due to the loss of their general and the moral is broken as their base has fallen, so most flee and the rest of them are taken care of by the hawks. In the end, this battle was more of a drama, it was set up that Governor-General Gennon who was put in charge of the Fortress and Griffith had to prostitute himself to, and he felt defiled by him but what made the battle and eventual confrontation with Gennon amazing for me was that Griffith had overcome Gennon and only saw him like a pebble on road not worthy of resentment or endearment, and that’s how most the battles in the Golden Age are, character dramas conveyed through battle. Now Griffith’s character, when we first see Griffith in the Golden Age we see a beautiful, charismatic young man who acts childlike, is a genius at the sword and is trusted by his men but then we find out about Griffith from the way his men talk about him and his interactions. Griffith was a commoner who grew up in a feudal class system that grew up idolizing castles and kings, so he set out to make a name for himself and acquire his own kingdom and that's why his men idolize him because he held to his convictions, strives to achieve them and succeed each time. Griffith is someone who acts like a sociopath because he shaped his life around his goal of having a kingdom and but he isn’t truly like this and the manga goes to lengths to show this in Griffith’s interactions with Guts and Casca, Casca’s flashback and Griffith’s hallucination when he became Femto. Despite, what a lot of people say Griffith was a kind-hearted person who deeply cares about his men and saw Guts as his dear friend above everyone else, his kindhearted nature is shown when he saved and comforted Casca as a young child, he obviously did this as an act of kindness and morality because as a child Casca had nothing to offer him. But we saw the impact Griffith’s dream had on him and his relationship with the hawk, this is shown in Casca’s flashback when Griffith saw the boy who died in battle, only he remembered the child and he was heartbroken, these two things showed Griffith’s relationship with the members of the hawk, he deeply cared about the members of the Hawk and even if he didn’t consider them as friends or that he rationalized to himself that they died on their own accord, he still felt responsible and if there was something he could do (like prostituting himself to Gennon) to honour the death of those who died and to prevent as many deaths as he could. Griffith was also someone how held a believe that people should spend their chasing their ambitions and believed that his friend could only be those who were his equal with a deeply held ambition that they strived to succeed in without being compelled by others(this is why Guts left the hawks, he wanted to become Griffith’s friend, his equal) but paradoxically Griffith deeply valued Guts and his feelings betrayed his convictions. You could say that Griffith’s fatal flaw was his own belief in his worldview, that's why he betrayed the hawks and Guts so he could put the pieces of his broken dream back together.
Now for Casca, Casca is someone how looked up to Griffith not just as a common “fangirl” but because he extends a helping hand to her in her time of need, giving her comfort and a new way of life. Miura also did this masterfully because he not only showed that she cared deeply about Griffith but what would happen when she saw her position as Griffith next to Griffith taken away by a usurper. Her loyalty and devotion to Griffith made her want strength so she will be able to serve sword in the pursuit of his dream, knowing how much of a burden his dream was on him. Because of this, she initially resents for Guts, she was jealous of the fact that he was more important to Griffith that her and angry because Griffith would put himself in danger for the reckless Guts. But aside from this, Casca was a determined and capable leader in the Band of the Hawk who and her leadership is so great that she is able to rally the Hawks behind her in their moment of and prevent their complete annihilation for a year following Griffith's imprisonment. Even during the Eclipse(before the invocation of doom), Casca does not allow the Hawks to panic and keeps them in formations. Casca is also shown to have a hardened personality but is this way because she wants to mask her vulnerability and her status as a woman is the source of her unease, and she masks it with a guard of sternness, lashing out with physical violence when she felt vulnerability(like when she had her period during battle). Beneath this guarded exterior, Casca wants to be accepted as both a warrior and as a woman, which she originally desires from Griffith but was able to get from Guts and it was anything but short she started liking him fully at the end of volume 8 and it ended after her being raped in volume 13 about 51 chapters. The rest of the Hawks did get characterization despite what you say I’ll make this part brief, the rest of the hawks who get screen time are Judeau, Rickert, Corkus, Pippin and Gaston.
Judeau was shown to be a kind, laid-back person and welcoming person seeing as he was the first person to interact friendly with Guts and welcome him to the hawks, he also has a keen sense of empathy and was able to understand the emotions of other people even when they suppressed them. He also was in love with Casca but because he knew Guts and Casca loved each other, he put Casca before himself in the hopes that it would make her happy.
Corkus always appeared as cynical person who talked big about himself but deep down, he was actually an idealistic person that's why he chose to stay with Griffith and was heartbroken when the person who he believed in was gone and his dreams were shattered. He also hated Guts because he felt that he was never fully committed to the hawks and because to him Guts acted like “he was the only one to bear any burden or pain in life.” But deep down he knew how much Griffith valued Guts( during the battle for doldrey he had a worried expression and after Guts left he reassured him it wasn’t his fault in his own way).
Pippin: He was very quiet and rarely spoke. When he did, it was often to make an important observation or to warn his companions, such as ordering the Hawks to duck against the arrows shot by Midland's soldiers or holding a cup to Guts and telling him to drink. He was shown as caring and loyal, and was always accompanying Rickert, the youngest member of the Hawks, and made sure to protect in battle. He did not get angry easily, retaining his peaceful expression even after being elbowed by an unappreciative Guts.
Gaston: Gaston was one of the Raiders that had a deep respect for Guts, both as a commanding officer and friend. Gaston never regretted joining the Hawks, but, as Guts said in the campfire of dreams with Casca, he wanted to save up his earnings to open a clothing shop in Wyndham. He was unable to achieve this, after being outlawed like the other members of the Hawks, but as he said to Guts, he wasn’t disappointed, instead, he was joyful that his place was with the Hawks and that the Raiders were a family to him.
Rickert: He was always shown to be a gentle and innocent member of the hawks and he initially idolized Guts for his strength after he saved him during the night raid but this eventually becomes friendship. His gentleness in conjunction with his more rational(emotionally strong side) side was the reason he created the hill of swords as a way to honour the hawks, as opposed to going on a quest for revenge like Guts. That’s why he only slapped Griffith when he met him, he was someone who sure he felt pain from his loss but he moved on and held on to the people he cared about Erica and Godot and it was also him rejecting that with was created with the deaths and suffering of the people he cared about. His greatest attribute is his intelligence and engineering skill taught to him by Godot and this has been shown several times in the story.
And the eclipse wasn’t shallow because we did see the Hawks has friends and how much they admired Griffith, the first time was how much they were worried about him during the first Guts and Griffith fight, the banter they have, how much the trusted Griffith during the first night raid, they party together, had fun together and extended a hand of friendship to Guts, the fact that they are quick to jump in to help Guts and Casca when they are in trouble and after Gaston was ready to stand up for them when they were accused of breaking their line to engage in personal combat, they were so worried when Griffith nearly died that they jumped to embrace him, Guts’ men cried when he left and when he came back to them. The hawks were also ready to stay with Griffith after he was a broken man and Guts raiders loved him so much that they didn’t want him to go again and where ready to follow him. Their camaraderie was far from hollow.
After the GA arc, it wasn’t just “Guts becomes a softie and gets friends, like in some damn Shounen. Throw in lots of fanservice (mindless gore and rape)”, the lost children chapters was a coming of age story for Jill, it also showed how wrathful Guts could be but through Jill it worked to humanize him showing he could be protective of someone else and inspire them to grow up, and gave the most sympathetic villain of the series(Rosine), the incarnation ceremony chapters was a sekaikei(an individual societal drama) that gave us amazing character like Luca, Jerome, Farnese, Serpico and one that I don’t particularly care for but is actually well written(Isidro). Conviction arc was there so Guts could change and become a better person with and find people who he cared about, so he could make a “conviction” to himself that he would never abandon those who he cared about and for Griffith to come back and complete his story arc. Falcon of the Millennium was there mostly for Griffith but it was a well-done story arc, it fleshed out the world of a Berserk, gave us an interesting villain, let us see Guts as a father figure to Schierke, a mentor to Isidro and a leader and role model to Farnese, it also set the stage for the next half of Berserk and allowed Guts to start to complete his character arc and move away from revenge and gave characters like Owen, Silat and Laban their own story arc. Fantasia, this was mostly just a questing arc and nothing really happened aside from introducing new characters and showing the results of their journey(Isidro becoming a warrior, Farnese practicing magic) but it as started Rickert’s character arc of being the protector of Erica and let us see Rickert’s response to Griffith and the loyalty of Griffith’s war demon and also the interactions in Griffith’s kingdom and completed the Casca’s insanity story arc.
As for character arcs not progressing, Farnese’s transition from knight templar with a repressed emotionally nature to doormat to someone who has started standing on her own to feet and atoning for her past, Serpico learning to let Farnese live her own life, Isidro learn to become a strong swordsman and starting to care for other people, Schierke coming to understand that the human world isn’t just filled with vulgarity and ignorance and opening up to people other than Flora. Finally, if you don’t like the story okay, in the end, art is subjective but I just completely disagree with you. Oh and just to add something how is Guts getting companions like a shounen(having friends isn't something unique to shounen), I have never got this and even if it was like a shounen what's wrong with that, that's hardly any criticism.