What was Kripke's plan?

Does anybody know some ideas that Eric had for Supernatural and decided to change them for this یا that reason?

For example, I know that Anna was supposed to do some things that Cas did cause the شائقین liked Cas better then her.

Jessica was supposed to be evil یا possesed.
The دکھائیں was supposed to be about a journalist.
John was supposed to appear in DALDOM insted of Lisa etc.

Do آپ know anymore interesting stuff like that? Does anybody know the plans for Bela یا Jo (if it wasn't for the پرستار hate)? How season 5 was supposed to end?

Thanks!