10exp is like 90 expertise rating
if u dodge AA u dont get Art of War proc and also u dont stack seal of vengeance on him
and u parry a lot vs dks or dodge vs rog,ferals
more exp=more dmg=more healing
exp is not useless in pvp especialy on class which doesnt have ability like overpower or rune strike to get value from dodging/parrying
exorcism doesnt do much dmg and it has 15sec cd and in 2s most of the time i use all art of war procs for flashes and exorcism only for burst