The biggest problem with the thorey is that doesn't explain anything.

the only thing you said here was that 'kakashi' lost his eye in a battle against the Kyubi and had to take an uchiha eye. it still leaves his past and the 'real' owner of the eye unclear.

besides, how can you explain Kakashi's actions with this theory? like why is he always late or who were his teammates and who was obito-san?

and the last thing, you say that his mission was to take care of naruto, and so far, Kakashi done nothing like that, he has practically left naruto on his own during the last 100 chapters of the manga.