Isn't this a misnomer? Since the HEAD is the governing part of the body... shouldn't this be called and entire body transplant?
Oh heck, this is becoming somewhat complex.
You suggest the head is the governing part of the body. I'm not so sure I can agree with you.
... The human body is made up of three distinct areas - the physical, the psychological and the spiritual. All are interdependent upon the other.
...... The spiritual aspect is the will to live, and probably includes the individual personality.
(Please, don't ask me about the soul. I'm not your man to talk about that).
If, as you suggest, the head is transplanted onto a different body, it might be considered both a head transplant,
and a body transplant.
Further considerations:
If it was possible for a very rich man to buy himself a new body, thereby extending his lifespan, would it be ethically correct?
... Bill Gates? Donald Trump?
Similarly, if a person with outstanding human mental facilities, Einstein for example, should he be considered for a head transplant for the benefit of mankind?
... Steven Hawkins?
Brain aging related conditions such as dementia will be preventable in the near future. I doubt if it will be recoverable should it be left untreated.