I like the family tree in Rome 2 alot more than i thought I would. It's certainly a better mechanic than in Rome 1 or Med 2 as it has more functionality than in those games. Though those games traits system I think is better. In Rome 2 it is more deterministic eg compare how techs are researched in Sid Meiers Alpha Centauri compared to Civ. Could do with some more interaction with characters in Rome 2. Thinking of story packs though something along the lines of Way of Life/Conclave for Crusader Kings 2 or those that have been relased for Stellaris. The tech trees especially for the civic techs is a very simple implimentation of the Nation Focus mechanic in Hearts of Iron 4. We could do with more elaberate tech trees. I'm quite a fan of the tech trees in Endless Space and Civilisation Beyond Earth. Note: That's as in style wise not let's research Roman space marines....
I don't feel the need to buy another campaign expansion. But a DLC with more campaign mechanics, role playing elements I would very much like that.
Needs a population mechanic.
The auto resolve is too heavily weighted towards you using it compared to how it was in Medieval 2