Um. Any (all) player(s) getting to fly whatever they wish whenever they wish is a level playing field. Where's the 'suspect' in the analogy?
Micro-purchases would not be a healthy or productive business model change for AH, given the player base, imo.
Minecraft teens apparently don't mind their parents shelling it out. This ain't Minecraft and the player base isn't primarily teens being subsidized by their parents.
The problem is people are NOT flying anything or everything. They are sticking to one plane/gv/style of game play. There is no incentive.... or to look at it from the other side no deterrent to lead them into other avenues of game play.
I don't think adding micro-purchases is going to help any. Like the chess match it would hurt the "level playing field" of the game play. Also as many have said right along Aces High is one of those niche games and what works in one type doesn't necessarily mean it would work here.
I'd love to see new maps, better graphics, ambient sounds to fill in the back ground, bridges and beach heads and maybe even trees that won't flip a tank

But all that really doesn't matter that much. Sure those are the things that bring in players, but it's not why players stay. Players stay because it's fun. If the game is boring and stale because the majority of the players only play one style your not going to keep the players.
AW had crappy graphics and the same map forever, but we had a great player base because it was fun. We did it all in that game, here you see the same thing over and over because the majority of the player base looks for only one thing..... the quickest, fastest, easiest way to grab bases to win the war.