I've been in several excellent GV fights only to have them ruined by bomb****ing Lancasters. Hell, I've even seen other countries complain that GV fights were ruined by their fellow countrymen.
Is there spawn camping? Sure. Even during a spawn camp situation, getting into a firing position while taking fire is still a challenge in itself.
As to additional vehicles that could be added with a minimal amount of work...
Stug IV, Jagdpanzer IV/L48, Jagdpanzer IV/L70, Brumbar - are all 'new' vehicles that use the existing Pz IV chassis.
SturmTiger would use Tiger I chassis
M10, M36 both use the existing Sherman suspension and running gear, sponsons and upper hull would have to be modified, but the moving parts are already there.
SU-85, Su-100, Su-122 - all use the existing T-34 chassis.
There's 10 vehicles that could be added using chassis and running gear that's already in game. That means only minor modifications to vehicle performance data, speed, etc., and more than likely, utilize an existing gun sighting system based on existing vehicles.
OK, so an SU-85 has the same gun as the T-34/85. Since it has a limited traverse, don't perk it. Upgrade it to an Su-100, you still have limited traverse, but you've got a better weapon, so perk it for a couple points. Su-122, you got a portable town killer, but not great against against tanks at longer ranges. Some thing with the Stug and Jagdpanzer IV series. Perk the L70...perk the M36, perk the snot out of the Sturmtiger and Brumbar, using them as hangar and town killers.