Outside of the top two, I think it is really up for debate and they probably would've done themselves a service by rounding out the top ten, as there are many potential oversights here.
I wouldn't consider Askren's as a top five personally, if only because he isn't fighting anywhere near the WWs with TDD that the UFC roster offers and that his style of wrestling leaves him wide open for submissions, which I believe could be exploited against a higher caliber fighter.
Names I'd suggest be added into the top tier conversation include:
Rashad, Davis, Gray, Mo, Cain, Sonnen, Woodley, Munoz and Hendricks, maybe Mendes and Volkmann. Outside of ZUFFA alongside Askren, I'd recommend Nathan Coy and obviously Bubba Jenkins and Joe Warren.
Also, there is a really big difference between MMA wrestling and NCAA wrestling, catagorization is very subjective here. Are we going off of credentials or applicability in an actual MMA bout?
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