Gameplay in a lot of MMO flight-sim games has always seemed to suffer.
I think it's a case of people losing sight of the forest for the trees and resorting to the "throw stuff at the wall and see what sticks" school of game design.
Right now, I can't really say that AH is really a "game" (a past-time which rewards good decision making and punishes bad decision making) in the true sense of the word, at least at the "macro" level.
Basically:
1) At the "micro" level (air-to-air combat, GV's, bombing), I'd say AH is "above average"...basically, air-to-air combat is good, GV's I don't know much about but bombing seems to be pretty porked in that the skills that separated good bomber pilots/crews from bad ones (there's that decision making again) aren't rewarded in the game; with that being said, I'd still rate AH "above average" at the micro level since most people mainly seem to be interested in air-to-air combat so at least HTC is keeping the majority of its client base happy.
2) At the "macro" level (the level above the air-to-air fighting, i.e. the strat), things are kinda porked. There's no real "game" there, at least not in a real sense of the word. It's basically just thrown there as an afterthought but it's not surprising since most people don't seem to be bothered by the fact it's porked.
The real challenge is going to be finding a way to implement a real "game" at the macro level without porking the game at the micro level; to put it this way, at the macro level, each player is essentially a chess piece in a game of chess; and people might have fun being a pawn initially but after they realize that they can only move one space forward and that's it, they'll all pretty much gravitate to being queens because that's more fun. However, if you try to play chess with all queens, it turns into a pointless exercise; there's no more game there.
Now, the question is should HTC even devote time to improving the game beyond just the furballing?
The way I see it:
a) The majority of the players seem to ONLY be interested in furballing. So why not just change game play where you have several side vs. side death matches which start periodically (that way, if you get shot down, you just find another side vs. side death match on the server) and then have at it?
b) However, after a while, that may get boring and people may want a more complex "world" to interact with.
c) So we add a strat layer. However, any meaningful strat layer (at least one that I can think of off the top of my head), is going to involve punishing a side for making poor decisions and when that "punishment" trickles down to the players on the losing side at the micro level, suddenly, it's not so much fun.