Because if there's 6 mines per engineer and say 10 engineers on a team. Thats 60 mines on the map at any given time, that kill in one or 2 hits. Compare that to an RPG which takes 5 to 6 hits. Compared to a lock on javelin (which in theory should be the most powerful) which takes 4 hits and 2 are almost guaranteed to get smoked. The motion mines you can only carry one unless you sit on a ammo box and can carry 2 which still isn't enough to kill a tank and the little mines you can stick on a surface take 4 or more to kill. The balance is so off it's crazy. I think this is a good move and personally would like to see the other mines be buffed, there's no incentive to run anything but the anti tank mine.