If you have been living in a cave you may have missed that Diablo 3 has been announced and blizzard has a small teaser website with 5 minutes of footage and artwork and hours worth of speculation all across the forums.  There really haven't been any major updates since the website went public. 

Execs at blizzard are saying the reason they are bringing back the barbarian is because they felt he could be done better.  They felt he wasn't done well enough in the previous games to take him out.  Blizzard has no plans however to bring back anymore of the previous cast members. 

One such member that will not be making a comeback is the necromancer.  Blizzard felt that they had done him correctly and he was near flawless in his design.  The witch doctor bears some of the similarities of the necromancer but many people argue that they feel it would be too watered down from the original necromancer to be of any use.  Only time will tell.

http://kotaku.com/5039711