AOH2 would probably be better, at least for mobile. AOH3 still has problems for android and it would be a wasted attempt just to port it, as it would likely just have more problems that everyone would demand to be fixed. AOH2 still rocks, so there's no need to overcomplicate things.
like victoria 3 when you can demonstrate interest in certain land, and it affects directly in game simulation; for example, prussia has interest in all germany provinces, and as time passes, they will be more like they interest look like, and the interest land of each nation could be customizable in scenario editor