Ideally, I would like for the V vs V and V vs I balance to be like this:

Heavy vehicles should be very effective against all forms of vehicles
Heavy vehicles shouldn't be very effective against infantry
- As it is meant to be the heavy hitting vehicle, the tank should absolutely wreck other vehicles... but this should come at the cost of effectiveness vs infantry. One way to reinforce this is to make all tank weapons have little to no splash radius.

Light AV should be effective against light and medium vehicles
* Light AV can also either be very effective against light and medium vehicles or also be effective against infantry (not both)
Light AV shouldn't be very effective against heavy vehicles
(Light AV in large groups (4+) should still be able to combat heavy vehicles with good coordination)
- The greatest asset of light AV should be its versatility. Weapons like the PLC can be effective methods of fighting infantry (or they would be if CCP got around to buffing them...). However, weapons like the Swarm Launcher cannot be used against infantry and thus should be even more effective against light and medium vehicles though not through damage. E.G. The swarm should have a large range of attack and the missiles need to be fairly fast in exchange for not having the ability to fight infantry (they also need decreased ability to turn so vehicles have an effective means of countering them).

Heavy AV should be very effective against all vehicles
Heavy AV shouldn't be very effective against infantry
- Same as heavy vehicles, heavy AV should give up its ability to effectively fight infantry for the ability to effectively fight all vehicles.

Medium and light vehicles should be effective at fighting infantry and other medium/light vehicles
Light vehicles should have less power and defense but have great speed and handling
Medium vehicles should good power and defense (not tank levels) but be slower (again, not tank levels)
(Same as light AV, medium and light vehicles in groups should be able to take on heavy vehicles)
- These are the vehicles that pilots should look towards to fight infantry (along with their non-combat roles like troop transport)

I feel these guidelines would create a V/AV dynamic that would result in more enjoyable gameplay and give a clear idea of how to balance new vehicles.