They've also varied the recruits a lot more throughout the game. The CGI Revelations trailers are also 'more aligned' with what actually happens, unlike Brotherhood.
Yes Ezio will get to meet more unique faces and recruit new Assassin's in a less cookie cutter style in Revelations, and the Brotherhood will get better chances to perform "specific things" for our aging lead character. They're focused on a lot more.
Also the Revelations CGI trailer actually has a strong bearing on the events in the upcoming game, unlike the courtyard showdown in Brotherhood's teaser. Assassin’s Creed III has been confirmed to be moving ahead once Revelations is done.
Assassin's Creed: Revelations releases on Xbox 360, PS3 and PC in November.