I call FUD
Reboots are not required by SP1 - although the install dialogue could be a little clearer: http://sqlblog.com/blogs/aaron_bertrand/archive/2009/02/26/sql-server-2008-sp1-setup-is-a-little-confused.aspx
I can't remember when I last had to reboot Windows following a SQL Server service pack. I would guess it would have been SQL 2000 service pack, about 6-7 years ago, but I could be wrong - it might be even further back.
As for new features - its a service pack, not a revision. Since when were new features required for a service pack?


