Just a tidbit of information (that may be wrong now), but a few updates ago when I was in CtF PvP, a few bards were fascinating my monk. That's fine, found that I can Kukan-Do them mid song to break their animation and avoid the fascination.
As for Monk's vs Barbarians
If no abilities are used and you want to PvP. It's been said already, just go and roll two identical charcters, give both basic korthos gear and then see who wins out. That is 100% FAIR PvP.
Otherwise, everything and anything goes in PvP.
Although consistently using stuns, holds and songs are frowned on and can get you into trouble.
J1NG