Trouble getting real neurons and synthetic neurons to interact would certainly throw a wrench in everything, but I am not so sure that concerns about changes to the individual are much of a show stopper. If you are digitizing a "person", they are going to be dramatically altered one way or the other.

Either way though you are going to create an intelligence that will likely be unable to relate to biological people, and biological people will probably have just as much difficulty relating to it. I wouldn't be surprised if an uploaded person was viewed as some sort of psychopath after the procedure, no matter how perfect the procedure was. (And considering how biological people will probably treat it, it would probably be very justified in thinking the same of them)

As long as the individual is happy with the results, no matter how changed they become, that is probably the best we could hope to shoot for.