Morrus - that's a fair point, but I could substitute the word 'expectations' if you prefer.
On the internet a lot of time you get the impression that D&D players now expect to be able to make up anything they want for any game regardless of the individual DM, world, etc. That's a lot of work for a DM to cope with, if I have to take on a Troll PC with a couple of prestige classes from strange books or whatever.
I guess the question is really about what makes a DM a 'bad guy' if he leaves it out.
I answered #2 because I think that if I sat down to 'play D&D' with a new group of people and discovered that I couldn't make a human fighter, or had to make a dwarf bard with jester as one of my perform skills because the whole party was a troupe of dwarven buffoons, I'd feel like the DM was pushing too hard. I might play anyway, but I might not too.
On the other hand, if someone said no elven paladins, or only elves can multiclass and only as fighter-wizards, or no gnomes, or something like that, I'd probably say oh, OK, that's how you do it around here, fine.
I'm trying to figure out what the baseline expectations are that people carry around with them for getting into new games. I think the answers are complicated because there isn't as much 'casual D&D' out there as there once was (people tend to play with regular groups more now then when I was coming up in the seventies) but I'm curious about what today's expectations are.