It’s no secret how Daniel Cormier feels about Cain Velasquez. He has said time and again that he feels Cain is the greatest heavyweight to ever walk the Earth. Stipe Miocic had himself a hell of a run in the heavyweight division, but DC doesn’t feel that makes him the greatest, just the most accomplished.
Many fans are numbers and stats people, so they would disagree with DC. However, I think he has a fair argument. In a similar case, you could argue that Fedor Emelianenko is the greatest heavyweight ever. Both stats and skill attribute to the makings of who the greatest is. I personally feel that Fedor is the best heavyweight and possibly the greatest fighter ever. What it comes down to, is just personal preference.
In DC’s case, his opinion is that Cain is the GOAT. He may very well be correct. It just depends on if stats or skills are your preference.