You need it, if you want reliable, acceptable skill perfomance, and access to most feat.
My stats are Str 3, Dex 6, Agi 6, Const 3, Int 6, Will 10 at start, Perception 6 (Snooping, Nimble), + Cave Hopper boots\armor (+1 Agi), + Adaptive Goggles (+1 Perception).
Crit around ~200 with Neural Overload, because of 136 Psi skills, Psi Headband that give +24% crit damage, and Cerebral Trauma feat with Locus of Control.