Sting is the single most overrated wrestler of all time. Period.
Allow me to clarify that statement; let me be very clear that I am not by any means stating Sting is a bad wrestler. What I am saying is that Sting is a good wrestler, who is undeserving of consideration amongst the elite of professional wrestling.
To start this off, let's take a look at Sting's abilities as an in-ring performer:
At his best, Sting was a slightly above-average worker, who could be elevated by a top-tier worker into having a great match. In his best matches (versus Flair at Clash of Champions 'XXVII, vs. Great Muta Great American Bash 1989, vs. Rick Rude at Clash of Champions XVII), the majority of the greatness came from the man standing across the ring from him.
Sting was never really capable of taking a match and leading it to greatness:
Sting's average matches are not anything you would want to take time out to watch, if one were on. A large part of Sting's limits as a worker, were his inability to adapt as the ravages of time took their toll. Even at the height of popularity of WCW, Sting had devolved into a much lesser athlete than his runs in the late 80's, and early 90's.
Despite the inability to work his older style well, Sting continued with it, rather than adapting his style, which led to him amassing an inordinate amount of mediocre to bad matches.
Sting's work in the ring is actually the strongest aspect of his abilities as a professional wrestler. In the earliest years of his popularity, Sting was absolutely atrocious on the stick. The majority of his promos were not passable for even average, or half-way decent.
To Sting's credit though, he did work on and improve his promo ability as time went on. During the late 90's, he could cut a mediocre promo on a somewhat regular basis (even good ones at times) and the one redeeming quality about his time in TNA, has been his vastly improved mic work.
Sting was, undeniably, one of the most popular wrestlers of the 90's boom period:
There is absolutely no debate to be had on that. Popularity though, does not equal greatness. Case in point, The Transformers movie franchise has been extremely popular, raking in a ton of money, but would anyone with critical-thinking skills consider any of them amongst the greatest movies of all time?
One of the biggest factors people bring up as support for Sting's status as "an all time great", is his popularity during his feud with the nWo during his 'Crow' gimmick.
During this period, Sting didn't talk, or have a match -- for an entire year. He exploded in popularity on the basis of standing against the nWo, not based on his own abilities. Nearly any wrestler would have gotten over, if they had simply traded places with Sting, and had been under the face paint with a bat against the nWo.
With his body of work, and talents as a professional wrestler -- Sting is the very definition of "The Hall of Good".
As always, here are the matches of Sting: