Okay, a few notes:
Staffan: Perhaps it was fulfilling a wish. But still, if such methods of wish fulfilment exist in the world, then we shouldn't be too terribly surprised by anything.
Heretic Apostate: This is a spoiler..... Buffy did not come back "wrong". She guesses that, but it turns out to be untrue. Buffy is fine, but as far as the chip is concerned, people who have come back from the dead since it's activation don't count as human.
In general, just before leaving Sunnydale, Spike mentions that he is not a true monster, nor a real man. He sets out so Buffy can "get what she deserves".
Now, if death were what she deserves, there was nothing stopping him. The only reason to get the chip out would be for wider revenge - to get at the Scooby gang. But he could manage that by proxies, and didn't need to go to such lengths to get the chip removed. However, if he truly loves Buffy (in whatever fashion a vampire can be said to love), what would he figure she truly deserves, huh? A real man!
Spike set out to make himself into exactly the sort of thing she fell in love with before - a vampire with a soul. She cannot love a normal vampire, because they are evil. She cannot love normal men, as they aren't her equals (as seen with Riley). What she needs is a conscience, backed by power on par with her own.