Of course it's not better and you would be foolish to think otherwise.
Those Avengers characters lead billion dollar movie franchises and have their own comic book lines going back decades. Some of them have their own movies... multiple even. None of the Spider Man villains lead their own movies, they are famous because of their relationship to Spider Man.
Hell we might still get some Spider Man villains like Venom, maybe Dr Ock. That's enough representation from one comic book series. We don't want an Injustice type situation where like a quarter of the roster is from the same rogue gallery (ie Batman and villains).
I know this is your opinion but god damn imagine the backlash if they don't put in stuff like Iron Man, Hulk, Thor, Captain America in the game. Would be worse than when they forgot to put in Megaman in Marvel 3.
I mean let's be real... just about every Marvel super hero has been an Avenger at some point anyway. Even Wolverine.