Well, we have a mature FM, IMO more than enough planes and a stable game. What about giving a boost to the graphics? That is, better fire and explosions effects. Better and more diverse terrain textures. More detailed terrain with forests (unable to ditch over them), rivers with ports only for PTs, roads, railroads, a lot of towns over the map, medium size cities, and the hability to take the towns and the medium cities with some impact over the strategy, etc. This is the factor where, IMO, AH is actually lacking more. Anything that make us feel more inside a real world and flying over real countries, not over moon surface from base to base and nothing between them.