Pinning down who is the greatest of all time can be tricky. This is the case in any sport. The criteria for what everyone looks for in the greatest to ever do it differs from person to person. There honestly may not be a true greatest of all time.
It's especially hard to pin down the greatest pro wrestler of all time. Unlike a sport like basketball or baseball, you can't look at a couple of stats and go about it that way. There isn't a home run or WAR statistic to look at for professional wrestling.
So you have to look at things such as in-ring style, your ability to sell, your ability to cut a promo, etc. The problem is that these things are also highly subjective. This creates even more of a challenge to pin down the true GOAT of wrestling.
However, everyone has their opinion. And recently, Seth Rollins gave his opinion on who the greatest to ever step inside a squared circle is.