Another very simple solution to reduce over-camping is to add in a publicly-displayed stat to the leaderboards and pregame lobby display that shows Average Distance Traveled per game for that game-type and featuring it as prominently as K/D and W/L. Making this stat public would discourage many people from camping or else this number would get embarrassingly low for them.
Also, fewer people would camp just to boost their k/d because people would be able to see who has a high k/d from not moving a lot vs. having a high k/d from moving around normally.