As roleplaying perspective, I'd like that. Psi Empathy pill I see as a permanently crippling shortcut to an ability that *can* be attainable through milder means.
Gameplay perspective though...It's free 25% health. Juggernaut without armor penalty.
However, since no respec or backtrack levelling...It'd force a player to spend points in one or two literally useless skills, until Psi is unlocked. If the quest would be available somewhere late game...it's a rather worthy reward for a rather ardurous endeavor.
Alternatively there could be two forms of Empathy...the pill one, decreasing health, or the learned one - but weaker. Maybe with less max Psi, or perhaps slower regen, or maybe higher cost per spell.