The thing is, no much how much more training, how much more practice, there is always someone, lots of someone, who are much better than you.
Now, if this is the real life military, where being better means life or death, I'd want no one else than the best of the best using my equipment. However, this is a game. There's always someone better than you. If we start using some kind of a competitional ranking to determine who is qualified to enjoy something and who not, then this would be the most awful game for someone to be in. Hey, why not start ranking who gets to fly fighters and who gets to be only in bombers? WW2OL, anyone?
The great part of AH is you can enjoy some of the most exciting vehicles WW2 had to offer, in a real-time virtual-warring environment. Everybody has a chance. Even those who are unfit, unhealthy, old, really young, bad eyesight, colorblind, and on and on and on. As long as you are a 15-buck subscriber, you can grab a plane and soar, or be in a gun and blast away.
Just because some clueless, sucky n00b wants to be in a gun, and be dismayingly inefficient and terrible at it, doesn't mean someone with a higher rank can come in and just push him away. The n00b is as much entiteld to a gun battery as is anyone, regardless of rank. That's the great part of all this being a game, and not a real war.