mythmere1 said:
everyone loses if there's no DM-to-player communication about the nature of the setting
Agreed, but keep in mind that "communication" does not equal "agreement". It MAY be that the best, most fun, most enriching course of action is for DM and player to go their separate ways.
If somebody wants to play a paladin on Barsoom, sorry, pal, but it's not happening. If the player is unwilling to move on that, they're clearly not going to have much fun in my campaign anyway, so we're both better off not playing together.
I think this whole conversation has confused two issues:
The degree of "cosmopolitaniness" in a campaign setting
and
The degree of "consistency" in a campaign setting
The first issue is how much variety in culture there is in the setting. Is the campaign set exclusively in the forests of pre-medieval Northern Europe, or is it set in full-flower Byzantium? You'll have a very different-sized range in cultural types in those two settings, but both can be perfectly historical.
The second issue is how much internal logic the setting worries about. If players can pick any cultural background for their characters, without any need to worry about whether or not the culture even exists in the setting, that's a low level of consistency.
These issues are unconnected, but it seems like people are posting here and saying they prefer more cosmopolitan (poor choice of word because I'm talking about something quite different than fusangite) campaigns because they have more variety. And yet I don't think Turanil's initial post was about variety vs. lack thereof -- I think he was talking about CONSISTENCY.
On Barsoom you can play a desert raider, a sophisticated urbanite, a veteran infantry soldier from a massive empire, a mystic witch-hunter, a sorcerer, a jaunty pilot of steam-powered airships, and many, many other types. Barsoom is a very diverse setting. It is not, however, very inconsistent. I work with my players to develop characters that grow naturally out of the setting, that come out of logical (if improbable at times) backgrounds.
I don't think the discussion of Variety vs Limited Options is all that interesting. I do think the discussion of Consistency vs Incoherence (there's a loaded term for ya) is kind of interesting.