@mracz guess it's just something that doesn't fit your tastes then. The story is really interesting, the author has a way in writing things out in a way that you want to know more and really see what the deeper lore/narrative has in store, and what mysteries will be revealed and etc. The pacing is done in a way that makes you just want more, as the author reveals bit by bit, just enough to get us craving more and wondering more of what's going on. Plus the characters are endearing as well, the art is excellent and the monsters look pretty creepy, monstrous, and well done.
I dunno about Berserk, but imo Shingeki no Kyojin kind of petered off in its popularity because it couldn't keep a good pace that had people wanting more and not get tired out on how little is revealed every time. Imo, there are a good chunk of people as well who dropped it because it was just too dark all the time without much break in between, and it's actually a good literary skill to be able to give reprieve to the readers and not always just have everything utterly depressing, dark, and hopeless. You'll lose a lot of people that way.