[Pros From Dover]

Honestly, the only time it bothers me is when they make a change that fundamentally changes who the character is.

Ripcord from GI Joe: Pissed me off. Loved the character as a kid and he wasn't a loudmouthed punk in the comics. I don't care what color his skin is, they ruined that character for me.

Kingpin for Daredevil: I didn't like it at first, but though it was ok in the end.

Nick Fury: Yes I am WELL aware that this is the Ultimate Fury, so don't bother pointing that out to me. And I like him. But I grew up with Jim Steranko's Nick Fury and associated mind blowing art. If you don't know what that is, you're missing out on true comic history. I'm not sure they could have found someone decent to play the non-Ultimate Fury after the Hoff screwed the pooch on his take of him.

Heimdall from Thor: Poof that race doesn't matter. In my mind Idris Elba owns Heimdall from now until Ragnarök.

You can't cast a white guy as Black Panther and expect to pull it off. That completely changes who and what that character is. Nor Captain America, he is the stereotypical skinny string bean white bread kid. Anything else doesnt work.
Fishburne as Perry White? Yeah, I can totally see that working perfectly.
Spider man? He could be pink with purple polka dots. The franchise lost me after SM3.