Re-write Draft 1

I really hate this part of the writing process. The fact when you have to sit down and face the first re-write of the next draft.
The part where you start to change character names, move scenes around, flesh out the smaller characters.
I wrote a semi-bio/semi-fiction back in 1998. I finished the story ...or so I had thought. Then in 2004 I gave it a satisfactory ending, only to have my computer die before I could back it up. Brilliant eh?
I didn't touch the story again depressed at the thought of not being able to recreate that great ending I had spent days at.
Till now.
So I pulled the story out the other week, for whatever reason it was tugging at me. And giving it a second draft have created almost a completely different story.
The fact that I could throw out 90% of the original story without care; does that mean I have become a better writer or just a colder one?