I'm not as sold on the importance of weight training.. but either Overeem is on year-round or both him and his brother have freaky genetics. His face and jaw looks three times than when he was at 205 which obviously means he was very drawn out at that weight. Not to mention natural progression as you age could possibly further attribute to his size.
I agree it's hard to say about Fedor's status in his career, the only person I really see giving him trouble is Overeem. Werdum is obviously better on the ground than Overeem, but he gettng Overeem to the ground is an entirely different issue. And submitting him would be a task for anyone, due to his training avoiding submissions and especially his freaky strength. He threw Duffee and Rogers (both huge) around like ragdolls.
As far as Arlovski goes, he belongs in this group much more than Rogers does. Despite his recent lack of success, the guy still has great hands and who knows how he'll come in if he gets some confidnce back.