One thing I see Ike criticized for, a lot, is his distinct lack of prejudice. To have Ike emerge from a world as screwed-up as Tellius with such an egalitarian attitude (especially when he grew up around people like, uh,
Shinon) strikes a good many fans as unrealistic. Fair enough, though really it kind of goes with the role of being the Game Hero, at least as far as
Fire Emblem is concerned. (Eliwood's own egalitarian bent could be deemed equally unrealistic, but I guess the "common touch" thing goes over better than "the not-racist in a totally racist world" angle.)
( It wasn't motivated by species hate; that xenocide kind of just happened along the way. )TL;DR, cut Ike some slack, I guess. At least in a big-picture sense, as you can still argue that the characterization doesn't entirely work. But he's hardly an isolated case.