For a number of years I have wondered what it would be like to have information be an asset (like gold or weapons). The sage/scholar tries to collect and assemble this, and is driven to quest/explore to learn new things. This could tie in with other types of gameplay. Storm an enemy keep to gain some info. Info leading to crafting recipes.
I actually think Vanguard kinda did this, where there were information brokers, and certain conversations would result in different information items that you could turn in. To keep with the sages idea, having the player activate a crystal ball within proximity to the point of interest could be a fun mechanic.
I pushed this idea for Vanguard, but they went in another direction. I suggested the idea that any game style (combat,crafting,diplomacy) should have raid content, and worked out a way for diplomacy raids to occur. They settled on that mini-game for 1:1 encounters. I was all about power=what you know.
Yeah, I have mixed feelings on the mini-game. It was at least an attempt to integrate diplomacy into a game mechanic, but it felt detached somehow from the rest of game play. But I do like the premise of building up different pools to draw from for things... I don't know. It feels like there's something almost there that with a little polish could be fantastic, but I'm not seeing what to touch up.
I also would really love it if there was some sort of way of talking your way out of, or through, situations. Too often in RPGs, even in Garriott's games, it feels that being a hero is defined as having a sword and introducing it into people's skulls. Granted, violence is certainly a part of life, and in RPGs doubly so! However, I did enjoy in games like Fallout 1 and 2 or Arcanum (done by Tim Cain), that getting through situations without resorting to violence was a perfectly valid option in many cases (Granted, in a lot of cases, sometimes you just gotta pull the trigger). Now, the implication is rather difficult, I'll admit. One can't really put in the dialogue trees that you found in the Cain games in an MMO all that easily. You could do what they did in the Bethesda Fallouts, but, personally, just having an option of "Click here to use your speech skill!" seemed way too artificial and disingenuous, I loved the dialogue puzzles from the earlier games, but, again, like I said, it's hard to do that in a multiplayer game. Vanguard at least tried with their card minigame, and I'll agree with Freeman, with a bit more polish, it could have really felt in game. Heck, you could have PvP "Duels" or "Debates" rather. And you could have some party mechanics as a committee or some such.