Thanks for your answer Ellay

If you crit for about 3500, 3% on each of your toons would mean 420 ekstra dmg on your em/ns/cl just from this meta. So I think its worth the tradeoff from gemming some blue gems. I am using two glowing shadowsong Amethyst in my gear (6 spelldmg/7stam) . This means that I am only sacrificing 12 dmg to get the 3% crit boost. Personally I think its a better tradeoff.