The PvP aspect you are talking about is already in the game. I personally alway play with a group of friends and this would make it very interesting to have all of us play a different role to make early game a little more dynamic. Its tough when we're all looting early on and have to split all the equipment up to where we all don't get to have a full set. And as for people picking soldiers to hunt other classes, right now in game I've come across someone with a gun camping newly spawned players multiple times, and its no different. This would atleast give you the option to defend yourself if you choose to do so, or get a head start in other areas, such as medical supplys, or hunting supplys.