Ping/lat and just coordination. If one of your crew gets disconnected or is slower than the others, you're dead. And then there's the issue they can't reliably keep the coms up. Imagine you want to pull a tanks after a "hotfix" but all the coms are down again. Sure, you can set up discord, which means you can't pick up randoms. Also I just fail to see how people could coordinate themselves for this to work. Everyone is just so focused on xp, they can't even coordinate a basic push/flank with their team. You think the dude who can't even let his team know he's about to crap a nuke on them is going to work effectively as a team vehicle? Idk, I don't think Planetside 2 is equipped for that. Also most of the community now has shifted from being tacticool to just brainless farmers. I don't see how you'd be able to convince people to give up kills for driving around. They would really have to buff the suitability of tanks if they were to detach the driver from gunner. Right now it's just too risky to place your hands in a driver unless you're in certain vehicles.