"Think of the great comics from your lifetime. How many of those comics were in the realist vein? Certainly none of the superhero or crime or sci-fi or horror comics you might enjoy. "
Stray Bullets immediately comes to mind. I've always felt the biggest problem is the pacing, not the performances of the imaginary characters. There are just too many comic conversations that inevitably will feel like summaries of conversations, not full-blown discussions. Think of the intense "Jew Hunter" opening scene in Inglorious Basterds recently. How many pages would that have to take up in a comic? A full issue? Only other way would be to have tons of text on each panel, which ruins the visual pacing (I think Kevin Smith has a big problem with this in his comic writing).