ok after a few hours of playing with it heres the low down.
Yonin: Frankly..it sucks. Too much -acc and not enough enmity+ to make up for it. Better off just straight tanking without it. Besides..it only works of the mob is facing u -.- which most of the time it wont be.
Innin: actually this ja works really well. Was getting close to 4/10 crit average on campaign mobs and I never saw a miss. The Enmity- is quite a bit. 1k Blade: Jin followed by 3 provokes with emnity+7 gear and still didnt get hate from a mnk. Acc+ is a good bit as well id guess close to 10? correct me if im wrong.
All in all i think Innin was a good addition but Yonin is severly broken for a nin that wants to tank well. Too much -acc not enough enmity+ (as said before). Enmity +7 (again from gear) + Yonin with provoke still could not keep hate off of an average geared sam. Also, the acc down must be pretty severe. With Yonin on with full ws gear, Blade:Jin only hit for 50 dmg (wtf...seriously...) but with Innin it hit for almost 900.
Just a bit a info on them incase some of you hadnt had the chance to try them out.
Edit: The evasion boost from Yonin is actually pretty high it seems. Tanking without a SH and still evaded 7/10 attacks from imps.