The doctor proposing to do this particular iteration is about half full of shit.
There is zero contention about the fact that you can do the stitching of the blood vessels and tubes and whatnot and have life support happen. Gotta deal with some CRAZY graft vs host disease with drugs, and there might be issues with the Vagus nerve being cut, but there have been head transplants on dogs and monkeys in the past.
But he proposes that he can regrow the spine. He is full of shit about that. There's been small success stories now and then but nothing reliable.
Now, some people might not want to become a full quadriplegic with autonomic nervous system issues who needs to be on a ventilator in perpetuity. Some might.
Here is the REAL ethical issue of such a procedure: the donated body being used could have been carved up into a heart, lungs, liver, pancreas, digestive tract, kidneys, bones, skin... you are using all of that on ONE person when you could have parceled them out and saved eight people.
Re: ethics
If the procedure works, you can estimate that its future application can be used to save N lives. You can assign an X% probability to the procedure working. As long as N*X is > 8, it would be more unethical to carve up the body and parcel out the organs.
http://www.businessinsider.com/valery-spiridonov-head-transplant-2015-4
Don't really have much to add beyond this. It's pretty awesome stuff though. The fact that this is even within the realm of possibility makes the argument for cryonics that much stronger.