So how do you know about vampires, anyway? Are they more common in your dimension? Are they out in the open?
No, it doesn't help. I still remember everything I did as Angelus. Every death, every person I terrorized. Especially the more recent ones.
Spike wanted his soul back. He went out and earned it. Angelus would never have done that. So he was already a lot closer to human than I ever was without a soul.