HW - They are getting pretty old. Nogueira is only 31 but has taken a lot of damage. Cro Cop seems ready to retire, Couture is old, Sylvia doesn't really look healthy anymore, Arlovski looks to have 2-4 more years, Gonzaga and Werdum both haven't taken much damage in their careers but neither has proven they are a top flight guy.
LHW Shogun and Rampage are both young and their is a lot of young talent in the LHW divison along with Wanderlei, Arona and Nogueira (if they sign) all being under 32.
MW - Really is all of these guys retiring a bad thing it's not like anyone outside of Anderson is very good. the divison is mostly in their early 30's and have about 3-5 years left.
WW - Loads of talent under 30 Hughes is the on;y one getting close to the end and thats just because he's been fighting so long.
LW - Lots of young potential but outside of BJ and Sherk their is no good fighters in that divison right now.