What the hell do Plato etc. have to do with this? The show isn't written by them. The only thing that matters is the world inside the show. And within the history of said world, Spike's statement is definitive. 'Make me what I was' is therefor limited to said character and said character's own history.
Freud has been largely discredited. And your obsession with the Oedipal complex, whether it actually applies to a character or not, is rather 'freudian
I've just been on Google Scholar: Buffy and Plato got 1,410 results. Buffy and Freud 2,720 results. Approx. 500,000 for each on Google. Let's leave it there shall we? It's getting off topic.