Instead of removing quickshot, just limit it to the time frame you can use it, like if you use it once you can't quick shot again for about 4-5 seconds, this is to prevent spam, the very thing 90% of the players depend on to win.
Remove Power weapons entirely, they should not be in a vs game, period. you don't show any skill needing a weapon that can 1-2 shot people. same goes for attack boosting skills, you don't get much health, but this goes without saying.
some weapons such as magnum and anit-matieral rifle's power need to be cut in half when used on other players.
Honestly, i can almost say giving survivor mode predators loadout would have also been a good option. learning to use ammo sparingly or be forced to melee. (with some exceptions of course)
"I'm sorry squeeky, it's just a game, you got to get before you get got"