I agree with Marvel has a lot of cool characters other than the X-Men.
… DC though? I kinda liked Teen Titans from the show as a kid, but otherwise I have yet to see a non-Batman character I thought was cool. Maybe Atrocitus, but from what I’ve seen, I only like his Injustice portrayal.
DC is maybe more than Batman, but the Batman characters are more popular overall for several reasons. One of those reasons, however, is recognizability… Even non-comic book fans knows about Batman, Robin, Joker, Harley, Poison Ivy, Catwoman, Penguin, Two-Face etc, because they have been exposed to them one way or the other.
People know Superman, but his rogue gallery not so much, maybe other than Lex Luthor. People know about Wonder Woman, but has the same problem as Superman. SOME people know about Green Arrow and Flash because of their Netflix series, but it’s a minority.
DC are trying to do something about it though with their movies and such, but as it is now, you can show Injustice 2 to a stranger and they won’t recognize 80% of the roster, but they will probably know who Batman, Superman and Wonder Woman is, and then the other Batman characters…
So being annoyed at people wanting Batman characters in a DC game is just self-destructive, because it’s not people’s fault for not knowing all the other DC characters!