Well, that pretty much answers our questions about choosing sides ("some have already chosen"). The mention of old villians in the letter, may also suggest the return of Minax?
I just realized, it kind of makes sense too. If you think about it, EAMythic has always been big on faction and realm warfare (Dark Age of Camelot and Warhammer). Its no suprise that Ultima Online might take some of that influence, and use it to their advantage.