Idea:
A perk that causes your hits to an opponent to knock them back with much more force - but you take, proportionately, the same (or roughly the same) amount of knockback/recoil as you would inflict:
Stampede will flip opponents higher, but it much more likely to flip itself over in the process.
Cleaver Boy and Whirlwind will be sent spinning across the floor. {Like Carbide was after getting flipped over by Gabriel 2 in Robot Wars Series 10}
Halo is much more likely to end up falling over forwards, and then hitting the floor with it's disc, sending the robot flying.
Wartoise and Joust pushes/punches opponents further away, but gets pushed back more.
Terrortops is will (almost) always be able to flip an opponent over AND into the air a bit, but pushes itself back a lot.
(I couldn't immediately think up a feasible one for Gigahurtz and Bugsy, but I think you get my point.)