Got it a bit backwards.
Rodiot didn't remove any cheat skills, rather he prepared a bunch of them for Van/Hiroto in advance because he knew someone with a huge soul was coming, but gave them to the wrong person. Without any cheats to take up space, Van is left with a massive mana pool, a side effect of which is that destiny attempts to fuck him over at every turn. (This is explained in, like, Chapter 1 and/or 2 of the novel, I think).
If you're wondering why Van has had such a good turn of fortune as Vandalieu, it's because
When his soul was traveling to Lambda to be born, Vida woke up, saw it, got reminded of Zakkart and decided to bless it with a bit of luck, so it could live a happy life. This was enough to overpower most of the "shit destiny" effect.
The reasons we hate Heinz are twofold. First, Darcia was the first nice thing to happen to Van in three
(four) lifetimes.
Let's look at the facts:
- Life 1 (Hiroto Amamiya): Parents died when he was an infant, raised by an abusive aunt and uncle who squandered his inheritance and insurance money on themselves, denied him the most basic of necessities as "luxuries", and would beat him for the smallest thing, such as having a new pencil that a classmate gave him after seeing Hiroto's pencil box full of literal nubs. Dies trying to futilely save someone, which she doesn't even remember.
- Life 2 (Experiment Whatever): Sold at birth by his egg donor to a research facility, tortured and experimented on daily for twenty years, gets killed by his handler in a fit of pique, possesses and reanimates his own body with his unique new magic and stages a break from the facility along with the other experiments only to be mercilessly gunned down by the very people who were supposed to help him the moment he gets outside.
- Life 3 (Vandalieu): Stripped of most of his abilities and cursed to never gain power in the conventional ways, lives for one year with his new mother before said mother gets captured, tortured and executed.
[*]Life 0 (Zakkart): Orphaned at a young age, had to work hard to make something of himself, summoned to fight in a war on another planet. The person who should be his best friend refuses to get along with him, he dies by being too much of a threat for the enemy to ignore, his soul then gets shattered by the demon king, and later on what's left gets composted by Rodcorte, along with the other soul fragments and the demon king's soul.
So, Van has gotten his first bit of happiness and unconditional love in multiple lifetimes, and the when it gets taken away from him the first thing he hears are people gassing up this "Heinz" fella as the one who caught his mother. So naturally, he swears a vendetta on the person who took away the one good thing that had ever happened to him. The whole thing is from his point of view, and all of us feel for the guy, so of course we side with him as the protagonist.
Secondly, and I had to have this explained to me as well, was meeting Selen in Orbaume, and hearing what Heinz has been doing since that night in Mirg. Van's reaction to hearing that Heinz has turned over a new leaf and begun protecting Dhampirs and their non-vampire parents as penance for what he did to Van and Darcia incurs the
very logical response of "why couldn't you have come to that conclusion
before you killed my mother?" And then after that, what really sealed the coffin is when, as in this chapter, Heinz went upstairs and let Edgar and Diana convince him that he was right and the vampire child was wrong because Heinz really was working to atone for his actions, and atoning nullified the crimes of his past. In that one moment, Ketchup's motivations went from atonement to sophistry, and
everyone hates sophistry.
Third reason (I know I said two) is PR. Van is the protagonist, and we want him to succeed. Never mind the mental corruption, cult of personality or even the fact that in spite of those two qualities Van is a decent guy; he's the protagonist of the story, and we're reading it because we want him to succeed. Van wants to kill Heinz, so we want to seem him kill Heinz, and the story gets us into Van's head so we can understand his mindset. Or Van's mental corruption is crossing the realms of fiction and we're all twisted.
But, a certain type of person is going to like reading stories like these, where the protagonist isn't a good guy, but they still wanna see what happens. Whether they're a serial murderer (Summoned Slaughterer), a war criminal (Nidoume no Jinsei), a rapist (Redo of Healer), an amoral death god (Overlord) or whatever the hell Kazuma is, we're gonna get into their heads, and make their problems our problems for as long as we read the story, because we want them to succeed.
TL;DR We're all fucked in the head, get out while you still can.