The primary issue at its very core is that vehicles have undergone a sort of tiericide, whereas AV weapons have not. What this means is that because vehicles are 'flat', but AV weapons are not, they're trying to balance a tiericided (sp?) role against a tiered role, which basically means the vehicles have to be balanced against a specific tier of AV.

So if you balance vehicles against Proto AV, STD and ADV are basically useless. If you balance vehicles against STD AV, then vehicles are nuked into oblivion by PRO AV. This is a fundamental flaw in the philosophy of Vehicles, and I think to try and expand on vehicles further without first addressing this issue would be irresponsible at best.

I think in general we need to move vehicles away from the concept of tiericide (Making infantry and AV undergo tiericide is an option as well) but the key is that you can't mix tiericide and tiered systems; it has to be consistent. Addressing this issue needs to be first and foremost on the vehicle issue.

That being said, once that is taken are of, there are a number of tools (modules specifically) that really should exist for vehicles. I'd personally like to see more modules made available since some obvious ones are missing, before we attempt to tackle additional vehicle roles such as Enforcers, Marauders, Logistics, ect.