hmm interesting, if thats the case I wonder how much crit you actually need. Atm I am at a base crit level of 36% + talents on top, and my surge rating is close to 70%. But after using shiv, stim pack, corrosive dart, corrosive grenade, shiv, cull....My energy level has fallen low making its regeneration slow already.
Atleast with Concealment we have a 0 Energy backstab, during that time, with stimpack energy can regen significantly quicker. Its interesting to see in time whats better with gear, sadly my last respec was 48k and I am sure it doubles each time