What I dislike about it is the assumption about the cultures of non-humans. Like ... if you visit a dwarven citadel, there aren't dwarf clerics? Or if there are, why couldn't they adventure?The race as class doesnt really bother me at all unless you are limited by stat rolls to play one. I figure old school play is quirky like that and dont expect race and class complexity to be the standard. YMMV.
I realize DM fiat can change the rules on NPCs, but it seems an odd rule, coming from my background in AD&D. It's not as strange in a game like HeroQuest where the world outside the dungeon doesn't matter. But now that we have options for other styles of RPG play, why not use those?