No way man. The annointed one served a far great purpose in BtVS. He ushered in a new era of irreverance, that created the landmark break of Buffy from the old movie style (prophecies, and sober responsibility) and into the new season2 style: Irreverance, chaos and mayhem. Ever the foil for the theme (in the first 5 seasons anyway), Buffy, too, changed over that stretch of episodes. She became more aware of her responsiblities, in counterpoint to the big bads' losing their sense of responsibility.
In my opinion. the Annoying one's greatest purpose, was to be fed to Spike to mark that break in theme in the most dramatic way possible. It was like a breath of fresh air finally let into a stuffy room. I laughed for 10 minutes after that episode. I had been wanting to do the same thing to the little bugger for quite some time. 🙂 Before Spike, being bad was never so good!