Indeed. The essential issue is that in a 16v16 game, one player should always equal one player, more or less. It's unfair for one player to play a class that it takes multiple players to effectively combat. I feel there are three avenues to fixing V/AV balance in a responsible way. I am not suggesting CCP implement all of these, just one of them:

1. Ensure that one tank can be easily killed by one AV. - This solution means that an AV player, one who has sacrificed their ability to combat infantry to go after vehicles, should be effective at killing vehicles. Tanks should have a hard time defending themselves against AV without infantry support. AV is the natural counter to vehicles, so vehicles should die to them. Tanks would likely need to be cheaper so that a tank + pilot suit combo wouldn't cost more than an infantry role.

2. Ensure that tanks require multiple players to be effective. - This solution would suggest decoupling the main gun from the driver's seat, so that tanks are most effective with two or three players in them. In that way, it'd be fair for two or three AV to be required to take them out. This prevents solo tankers from being very effective, but maintains the high cost and power of tanks.

3. Remove anti-infantry from the tank's bag of tricks. - This solution is more of a game-changer. Removing tanks ability to effectively take out infantry ensures that even if they remain powerful and hard-to-kill, that they can't abusively slaughter infantry, and can be balanced around anti-vehicle and anti-installation roles. In the current mechanics, this wouldn't give tanks enough to do, often. Ideally, tanks should have more tank-specific things to do in a game, like taking down barricades and shield bubbles.