I also quite like little useless RP props that your character can wear/carry or sit on, for instance.
There are benches in Eder Kemo in URU, that are interactive so that you can sit on them if you click them.
Same in WoW: tables and chairs in inns that you could go and sit at. WoW, though not exactly RP heaven, got a lot of things right in the props and clothing department.
As for a quest structure for fighting or crafting? I don't think you really need any of that stuff. Not as we usually see it, anyway.
In URU, an NPC would just request you to do something. There was no quest log, no nothing. You could just... go do it. Or not. Much more like RL. Someone asks you to do something, you don't have any kind of log, it's not like 'bring me x amount of this' or 'kill and y for me' and then you get 'this set reward.'
Even if the quests are not repeatable, in that form they feel a bit silly.
You really don't need skill structures and economy either. That depends a bit on the game though. If there's no combat you don't need a combat system. These kinds of things, fighting, death, economy, skills, cosmetic feaures, they vary too much from game to game. I don't feel that they inherently have something to do with RP.
In Seed we had no combat system.
In URU we don't have any system, really. And no one misses them either, they're just not needed.
I like NPCs that have actors behind them, but you can do a lot with artificial NPCs too.
In my ideal MMO for RP, I'd want as many people to come check out the game as possible. But of course, I wouldn't want to be swarmed by OOCers. And I don't think perma-death or lack of graphics are the answer. You punish everyone with that, not just the targets.
I think GMs might do a good job. Not having many features in the game that are much fun to do when you're not RPing would help too.
Seed's gameplay frankly wasn't much fun if you didn't RP with people at the same time.
In URU, all that is left for you to do, if you don't follow the storyline and get involved, is solve all the puzzles and look at the ages once or twice. Not too exciting either, you can only do that once, really. Though of course, you could just use it as a chatbpx with graphics. But I doubt many would do that once they have to start paying for it.
-Norah/Liath-
"Do not follow! The milk is not ready, and you are not ready for the milk!"
-Psychonauts: Milkman Conspiracy area