They could do things like make Footwork better (more likely to kick attack or make kicks more powerful), they could make Boost more powerful and last for a duration instead of "next attack" (and remove the stacking thing to compensate for it being less powerful) and give it a longer cooldown to compensate for that (basically, turn it into a psuedo-berserk, with perhaps shorter recast, but smaller buff).

But yeah, the main problem with MNK is the inability to do any kind of damage whatsoever with a weaponskill. TP for a MNK is almost useless. Ooo, look at me, I can hit something for 2000 damage with Spiral. Yaaay. *sigh*