There has been a very real, and quite large, change in the game. IMO it's because of the TV ads the the large influx of players that followed.
Much of AH, and what makes it what it is, exists in the players, not the game itself.(True of most online games) The emphasis on air combat vs base capture has always existed only in the minds of the players. Call it the community standard.
The standard is maintained when new players join the game. They learn the game from the veterans before them, picking up the same standard themselves. But when you have a large flood of new players, there are too many to learn from the older players, they begin to learn from each other. The community standard breaks down, and the game becomes something different. Usually settling at whatever is perceived as the 'best payout' of the game engine, eliminating the community standards completly.
New players learn that the goal of the game is to take bases. Said players fly the best aircraft to get that job accomplished, and will do so in the most efficient way. With the way AH is designed, the ideal strategy consists of much suicide field porking, and horde attacks on lightly defended bases. Air combat becomes secondary to taking bases. Unless something is changed, such player behaviors are an eventual certainty. (For better, or for worse, I'm not making judgements here)
When you talk to people who have seriously beta tested any mmog, you will almost ALWAYS hear that 'beta was better than release'. That initial flood of players can almost entirely wipe out old community standards, and replace them with new ones. It leaves the game substantially changed in the wake, and the old beta players wondering were thier game went.
Wether you like it, hate it, or don't care in the least, AH today is a very different environment from what it was before the TV ads began.