If the N800 would have more power it would be more expensive. The battery wouldn't hold that long. It would be thicker. The N800 isn't short of power. But optimizing the software to the platform the N800 uses would bring more. Just look at video playing. I think mplayer could be much faster on the N800 if it'd use all the processor specific capabilities.

I hope Nokia improves performance with the next big firmware release (Especially with video performance). Just putting in more isn't always the best way...