Nah Werdum's always been a deceptively good fighter. I always underestimate him because he doesn't come off as very dynamic. He's fought top heavies for the last 6-7 years and iirc besides JDS and Overeem fights has looked great.
I still don't see him beating Cain but at least we'll finally see someone other than JDS or Bigfoot fighting Cain over the last 5 years. I don't see this Werdum beating Cain or JDS honestly, tho who the hell knows what kind of fighting JDS will bring in future fights. Werdum is still the most legit opponent for Cain at the time being, so let's see it. Also I agree with Trax on heavies continuing to be good fighters into their 30's. IMO this is because average HWs aren't athletic (comparatively, don't shoot me) to other weight classes. You don't have to be a top athlete to be a top 10 guy at HW. This assumption fails at every other weight class besides Super Heavies. Also it's largely due to a shallow talent pool in the heavyweight division. With Werdum's skill and experience, as long as he doesn't get KOed he has a great chance to sub or nowadays KO anyone himself. Still. Werdum better pull a Werdum over Cain like he did Fedor otherwise he's getting beat the fuck up.
Lesnar's downfall was his struggle with diverticulitis. You could also say his mental game but that doesn't change how dangerous he was/is. Anyone who hangs out near 300 lbs, has wrestling experience, and is ATHLETIC is one dangerous mofo. If Brock developed his BJJ game earlier in life he could of been the Matt Hughes at HW with even more strength compared to his weight class.
If it weren't for his disease (and sweet, sweet WWE deal), I'm confident in saying Lesnar would still be ranked #1 or #2 at HW today. His striking and striking defense would of developed. Supposedly he's looking into fighting again as the WWE seems unlikely to extend his contract.