Re: John Harrison was more interesting than (SPOILER)
It does feel like somewhere in the process they went from Harrison to the Khan/Harrison villain. Maybe as late as shooting the film.
I think the Harrison facade could have been done away with completely and wouldn't have changed the movie much, as well.
"...the most elementary and valuable statement in science, the beginning of wisdom, is I do not know." - Lt. Commander Data, "Where Silence Has Lease"