This'll be an instance of "size matters".
Maynard is a HUGE LW and now that he's training out of AKA, he'll be working with cardio-centric minded grapplers, who'll have him wired to cut a violently grinding and FAST style. On the flipside, Pettis is quite small at LW and I think he gets put on his back and pressured for fifteen minutes, given zero room to breath and do what he does on his feet. I don't see Pettis keeping it on the feet long enough to be explosive and I think Gray implements his game to a tee and just bullies Pettis into dust.
MY MMA RANKINGS
HW Velasquez Cigano Werdum Cormier Bigfoot Barnett Mir Browne
LHW Jones Machida Evans Hendo Davis Goose Teixeira Shogun Mousasi Bader
MW ASilva Rockhold Belfort Weidman Jacare Okami Kennedy Consta Belcher Boetsch
WW GSP Hendricks Condit MacDonald Diaz Maia Fitch Kampmann Ellenberger Pyle
LW Bendo Alvarez Maynard Melendez Thomson J.Miller Diaz Pettis Chandler Grant dos Anjos
FW Aldo Mendes Curran Lamas Frankie Zombie
BW Cruz Barao Fernandes Faber Moraes