I got nothing (NOTHING) against Henry Cavill (other than maybe my body in a couple dreams for which I will not be held responsible), but I've been a long time Victor Webster as Superman proponent. I just...my god, why not? He's not a top notch actor, but he's more than decent, and LOOK AT THAT. He's Kent to me, for sure. What recasting would you do, given the couch^H^H^H^H^H opportunity?
And watching Spider-Man did make me wonder what Dylan O'Brien could do in the role—again, nothing against Garfield (actual nothing this time), but I've gotten used to watching Dylan play a brainy nerd who's willing to fight above his weight class, and he's equally good with comedy and pathos. Like, really good at both.
My other "this could fix things" recast is removing Renner from the role of Hawkeye, and casting Colin Ferguson instead. This is related to feelings.