I agree that the concept of retaining Humanity vs acumulation of power/ things is an interesting idea. I'm unfamiliar with Sorcerer, but Cyberpunk 2020 had a system for losing humanity the more metal you grafted onto yourself.
I'm not sure that you would have to switch to a new system to implement it. Using a system like Icon's "Honor" for Klingons or (What was it for Romulans? Glory?)... anyway adding a new stat and rules for increasing/ decreasing and otherwise tracking it to one of the current systems would work better. Sort of a melding of the two systems... say Sorcerer rules being used to track Humanity, and Icon or CODA rules for playing out the action.
I am a soldier. I fight where I am told, and I win where I fight.
General George S. Patton, Jr.