Halo: Reach is rumoured to be Bungie's final release in the Halo franchise, to be released on September 14th; but I think I speak for everyone when I say "we've heard that one before.".
Reach is set during The Fall Of Reach, which takes place just before the events of Halo: CE. You take control of SPARTAN-B312, Noble Six, the newest member of Noble Squad. Information on Noble Six is sketchy, at best; not even a picture is available. This does not mean that there has been a lack of character development; in fact it's quite the opposite. Though information about Six's past is unknown, the charcter is greatly developed.
Reach has been in production ever since Bungie finished work on Halo 3. With the time spent on the development of Reach, they have had time to completely rework character models. Some features of previous games will not feature in Reach, or have been reworked to give Reach a refreshed look and feel.