Well.. on every peace you most likely chose the best efficency. For example your belt: you will always choose 6 crit and 3 power, because those are the most efficent stats. No good dps player will ever choose 6crit and 4 crit on a belt, because 3power>4crit. Optimal ratio will always be 1power=2crit. So for your rings, you will always choose 4power, and then you choose between 2power or 4crit(depending on your class). Your neklace also will be 4power, because 4power>4crit. I think you get it now, you should always choose the most efficent stats, and if both are "same efficent", you choose crit or power depending on your class. (Only for DPS/TANKS). The only exception is Lunardancer, where you will always and only choose power, because crit is totaly useless most the time, so you go full full power. Same goes for Etchings. Unfortunately the KeenIV etchings only give 22crit (should be 24 but it isn't 
), where the PowerIV etchings give 12power, where you already see, that 12power >22crit, but this is "only" a 4crit loose. So you might still want to use Keen if you need the crit. (or Energetic which most of the dps classes uses now)
