This will piss a lot of people off, but suppose you only get credit for a kill if the target is wheels up? This would eliminate vulchfests, while preserving real base capture suppression. Also, if perks were awarded for anyone near a base that was captured if they did damage to anything there, that would be cool too. That would motivate more people to do base captures. You might want to allot a perk multiplier for mission kills too, which would make a LOT more people form and sign up for missions.