I don't think multi-player is appropriate or requirement for a game like this - I like the new tweaks in this game (mechanical changes) but I greatly prefer to cohesiveness of the first game as well as the maps. I'm a bit mixed about rage vs dragon but I think I prefer rage. Also resurrection could use a bit of tweaking relative to time back.
Having made those comments I would like to see a new game that has more puzzles and larger maps (similar to the first game). I would like tweaks to mark 'future' requests that might be broken if you go some place too soon (like kill an aggressive hero).
I think having too many widgest dilutes the impact of some aspects of the game and while this game probably did not go overboard it was pretty close; so if new features (spells, skills) are added to the next version then perhaps some of the older ones should be removed to prevent dilution.
Anyways these are some vague reflections of what I would hope from a third game without too many specifics. Oh and it would be nice if they could sequeeze in an editor and space ranger 3 with the package
