Probably MW, LW, WW, then the rest.
MW is stacked with Weidman, Vitor, Machida, Jacare, Rockhold, Moose and Kennedy at the top, and then contenders/gate keepers like Romero, Carmonte and Bisping. Then the possibility of Anderson coming back.
For the last few years I would have put LW on top, but losing Edgar to FW, Maynard's recent downturn, Nate's disappearing act, and not getting Alvarez, I think it's dropped down a notch. But you've still got Pettis (when healthy), Bender, Gil, JT, Khabib, RDA, as well as long-time contenders like Miller, Cowboy and Lauzon, along with guys like Michael Johnson.
WW is in a similar position, losing GSP without him (officially) losing the title, Condit being out long-term with a knee injury, Diaz disappearing, Fitch and Shields being cut, Askren not signing, Palhares being cut before he had a chance to really show what he could do at 170. Then you've got Maia and Lombard, imo, underperforming. Rory and Woodley are good fighters, but I don't see them as elite. And, as much as I love to watch them fight, if you told me two years ago that in 2014 Brown and Lawler would be fighting in a title eliminator (and that Lawler would have just a had a title shot) I'd have thought you were high.