Cops vs gangs was just an example of why this shouldn't be changed because it would hurt cops more than anyone and they are already relatively harmless. Keep denying the fact that cops don't get the same amount of love as gangs, but we all know it's true. You can get a cop friend or two to help you, but you still won't get a fair fight vs a single gang, let alone a few of them (which isn't really a rarity in the bank).
Ramming is overpowered? Not really, it barely does any damage at all UNLESS you drive full speed into someone, which then "drops" the guy. Driveby as well does minimal damage and can't even be compared to on-foot fighting. Nerfing the vehicles even more would be a disaster. If you want to speak about "overpowered" things, try getting on the ridiculous headshot damage and the one shot kill sniper/rifle.
Long story short, the current gameplay is already giving more love to on-foot fighting than vehicle/driveby. The way I see it, we should be balancing it by boosting the driveby damage, not killing it even more. That way solo players would at least get a chance to do something..otherwise, what's the point of playing if you don't have a dozen friends around you?