I've quite enjoyed the beta so far and the game is vastly improved over the original but it still lacks a sense of personal involvement with the Champions and the recruitable heroes. Interesting stories have been typed in but once you recruit a hero they are basically a stock pile for magical gear and a mobile can of whoop ass without definition.
What I might suggest is a series of quests that are linked to a defining generation trait of the heroes, possibly the same for the Leaders themselves . Link an ongoing quest such that stages would only be available as you unlock questing and if possible based on the level of the character, so you need to use a character and level them to get their rewards.
I would give the personal stories more meaning and might give the questing overall a bit more umph for being more diverse.