Not really sure if this is what you are looking for (and it's somewhat already been mentioned), but speed or DPS records would be something worth keeping track of, and right now pretty much the main source of "fun" for me in raiding until Sunwell arrives. We already have WWS, but it would be nice if there was an automated in game monitor that could keep track of how long it took a boss to die from the point it was engaged until death as well as the raid DPS. Blizzard seems to like take whatever is really popular, whether it's a mod or site and implement it somehow into the game. It could be similar to the PvP ranking boards with WWS lite. It might be too resource heavy though and impossible to implement for a long time though. Although with the upcoming changes to the combat log, who knows.
*edit, I guess there is already something like that in place, although it's still not an automated Blizzard feature.
WWS Scoreboard