You used to be so pure.
Of course, with current technology, they are paralyzed for life after such an operation. But can you imagine the funkiness involved in muscle memory and control?
There is a set of conjoined twins who allegedly share at least some brain functions.
Link.
And the woman (Eunice, the protagonists murdered secretary) somehow continues to inhabit the body, along with the transplanted male brain.
Heinlein is never explicit about the nature of the inhabiting Eunice, but I certainly read the situation (as a teen, when I first read the book) as a psychotic response to a highly unnatural situation - in other words, you would probably go crazy to some extent. People feel this way after other (less drastic) transplants, and particularly heart transplants. It has also been a factor to consider for facial transplants. Of course, something like a heart transplant is major surgery with complications and strong anti-rejection medications - personality and mood changes are common with such complex major surgery even without a new body-part. But the new part can become a focus/point-of-blame for totally explicable post-operative changes.
There was an interesting story in the papers just last week - a young man suffered a stroke and ended up locked-in, just able to communicate using eye-rolls. His wife just had a baby daughter before his stroke, and the neurologist suggested that the father be given play opportunities like the daughter (rolling, crawling, babbling), alongside his intensive physical therapy. The father started walking about 2 weeks after the daughter took her first steps. I have often wondered whether such a regression-to-infanthood based approach (from both sides, patient and therapist) would better allow new neural patterns to replace old ones, as opposed to trying to recover existing damaged pathways and being constantly frustrated. We take years to get control of our bodies (if we ever gain full control of it), so it seems logical to me that even as an adult we could take as long to regain control of a new body.
Si