The real issue with the vehicles is not that they are overpowered. Well, the hover craft needed an armor nerf, that was warranted. But the reason vehicles are so powerful is because the maps are wide open with hardly any structures for infantry to hide and move around in. If you aren't on the flag, you're out in the open in no man's land. One or two structures in the open are always crawling with infantry because they have no other option. And since there's 20+ people around it, vehicles go there to farm kills. Play breakthrough and just about every map has a couple sectors like this.
By keeping these vast open areas and just turning down vehicle damage, the kills might come down to a more balanced state but it's going to make the vehicles feel underwhelming and unsatisfying. What they should do is keep the vehicle damage high but give infantry more structures to utilize. That way vehicle drivers feel their weapons aren't marshmallow shooters and infantry doesn't feel like they are constantly getting slaughtered.
Also to add Soma, BF maps have always had large expanses of open areas between objectives generally with a few exceptions.
