I just submitted a First Impressions piece for the site on WITE2. I did not play WITE1 so I can't speak to any of the differences, but it's my understanding there's been a lot of improvements.
I'd say the WITE1 manual is better to have than nothing at all, but you'd need the new one if you want to explore all the nooks and crannies of WITE2...and there's a LOT of them.