With the abundance of healing this chapter wholeness of body doesn't see a lot of use outside a very minor ability to cut down on healing out of combat.
To give it a little bit of a cooler use I would change it to a player tool instant ability that can help quickly recovering from burst or surviving while disabled (the most dangerous time for monks) which might prove to be a more interesting alternative to just giving monks uncanny dodge.
Monks really should have uncanny dodge 1 as it is <_<
Wholeness of body is a bit rubbish anyway regardless of whether its instant or not, the three charges just saves you a couple of ash charges as it stands. It would be a nice ability though to give monks something they are missing while in keeping with the ability, I would propose:
1. Same healing effect of twice level hp recovered
2. Purge poisons (remove poison effect)
3. 1 round/level of spell resistance 2/level (e.g 16 SR at level 8 )
I always thought it was silly monks go from no ability to resist magic to 22 SR at 12. I would probably say keep it as an ability rather then a player tool if the above changes were implemented.