-According to you, Garth is now fully recovered and back in service as of "Going Boldly."
Which makes no sense to me. He was a killer and a nutcase as well as a shapeshifter. In my opinion, even if he is "recovered" he should still be in some type of nursing home. What if he has a relapse while on duty?
While it was nice to see him, it just stretches the imagination to think he would be re-instated to StarFleet.