my 2cents worth...
when implants were first introduced, it was a BIG warning what would happen to your humanity when you took them.
now there are more options, allowing you to tailor your implants a bit and salvage some humanity.
as said, the warnings are there....they have been there...and anyone who sacrificed humanity for cyborg implants....well???? there's a price that's paid besides the cash it costs.
I say don't let there be a system of returning back to human, unless there is MASSIVE repercussions.....like loss of all stat levels gained since the implant not to mention the cost of the surgery (it would like cloning you're original cells)
as for losing the stat levels...think about it...muscle memory....if you gained levels with a metal arm...put a real arm back on, it doesn't have any of the training the metal arm got. you shouldn't be able to keep the levels trained for.
the 2 cents from the man who's proud to have a 12 humanity