The only quests seem to be one of the following: kill count, gather count, boss kill, or lighting totems, and the former two are pretty much the same thing. What I am suggesting is some more variety to the story and the way quests are completed.

Raiding and destroying a castle, or even implementing a King of the Hill style quest where in one such map, enemies would continuously spawn, and you have to hold down an area for a certain amount of time sounds pretty fun to me.