If gold isn't a worry for you I would suggest re-specking to pick up Riposte. Its really useful if you are grinding levels since you spend so much time in front of mobs as combat spec. Like
this perhaps...
It really shines when you start taking 3 mobs at once as well, the +5% parry will reduce the amount of damage you take and if you try to focus on grinding against humanoids the disarm part of Riposte will also reduce the amount of damage you are taking. Parrying any attack will allow you to riposte, unlike Overpower the move isn't specific to the person who procced it. If that warrior who jumped you when you were fighting two other mobs had only been able to overpower you the fight might have turned out differently.
It is also excellent for dealing with other classes that rely on Melee. Disarm a hunter and he can't wing clip you for example. Shamans get much stronger in the 40+ lvl bracket, take away an Ench. shaman's weapon and you have much less to worry about.
This is just my personal experience but it really is worth taking, even more so at lower levels where having no weapon is far more problematic because classes haven't gained all their abilities yet and have far less ways of saving themselves than they do at lvl 70.