Kosak: In vanilla WoW, we had always loved the idea of group quests. You'd be questing along, and then you'd get a quest that was a really difficult challenge and you needed to get a team together for it. We loved that idea, and when you got a group together for those quests they were really fun.
Coming late to the game, I never was able to experience but I wish I could have. The closest thing I saw was questing in Northrend and getting some quests that suggested 3-4 players. I LOVED those. Of course I would always try to solo them and fail miserably most times, but then I'd level a little bit and come back and try again. The one thing I wish was different in questing is I wish there was a challenge. Traditional RPG games is that you go in the forest and kill some things, get some gold and xp, get better gear and increase levels. Go try the boss. Fail. Go to the forest, kill some more things, get some more xp/gold/gear/levels, try again. Rinse and repeat. This is lost in WoW. To the point that not only are the quest lines not challenging, you are generally WAY over powered for them before long and start jumping the chain.
But there was so much overhead in actually getting that group together that it was actually a pretty painful experience. And what happened in practical terms was that by the time the expansion had been out a few weeks, you could never get a group together to do daily quests -- it was such a pain that you never ended up doing them.
I don't think we explored enough possible solutions on this. The solution I would be after is "how do we entice the veteran players who have already gone through this content to come back through and help the newbies". This will build the teamplay they are looking for. Going back to my Gateway MUD example again, one of the things they did was create a mentoring system. You could become a mentor for a new player and as that player gained xp, you got a bonus to the amount of xp you would gain as well. In maxed out level WoW terms, think of it is getting a buff that increased your rep gathering. That would probably be something that would attract you maxi's back. And to help mitigate the people that are just trying to selfishly rush through it for the buff instead of helping the new players, maybe through some Ebay logic in there where the player gets a say in how well the mentor did. So if you're a dick, you don't get to the end game as fast being helpful.