Well, at the very least, they'd have more force behind them with thrusters added. Moreover, the legs themselves are probably modified in some way to make kicking while maintaining balance easier. Think about how hard many humans find maintaining balance while kicking. Adding thrusters, or chainsaws, is likely to make that harder. Especially on a miss. Might even have been called out in the weapon description, because I believe there was mention of stabilizer spikes? If we really feel like copying that Chainsaw maniac from Soul Eater, that sort of thing could help.
I think someone actually did make a Chainsaw Jaeger. Lemme check...
Yep.
@Sir Plusse made Sawmill Tempus a while back. No chainsaw legs, though.