Well, Ward is struggling to get fights at the moment (he's cleaned out 168) so I can see a rematch benefitted all 3 guys in terms of $$$. I suspect neither Kessler or Froch think they can win, however.
For both guys, I think fights at 175 would be logical. The champions there are weak (if you forget about Chad Dawson) and retiring as a two weight champ is good for the ego.....