Here's my take on it for what it's worth. Shane is definitely one of the greatest players of this generation, along with the top Filipinos, Chinese and Euros. I would put him in the top five players in the world today. That said, I have become convinced that the best players today play at a higher level than all but a few of the top players of earlier generations.
There still may not be a better Straight Pool player than Mizerak was, and Sigel was not far behind. Same goes for One Pocket with Efren and Ronnie arguably as good or better than any of the current crop of players. In 9-Ball the absolute best I ever saw was Earl at his peak. He could match Shane ball for ball and game for game. He put up similar packages to what Shane (and others) are doing today. Buddy handled the cue ball as good or better than anyone I'm watching now as well. And Sigel knew how to win, proving it over and over again. Let's not forget about Parica, the greatest money player of his era. Jose was also the best Ten Ball player for many years also.
But as good as Parica played the game the current crop of Ten Ball champions is definitely a level above the competition he faced. Parica would have his hands full battling Shane at this game, plus Orcollo, Yi, Chang and others as well. IMO the ten to fifteen best players in pool today are all the best players who ever lived! They have all learned to excel at Ten Ball, a much tougher test than 9-Ball, the previous yard stick by which players were judged (there were more 9-Ball tournaments than any others by far!). Twenty to thirty years ago no one was playing run out Ten Ball, other than Parica in money games. And he wasn't putting together packages like Shane is doing now.
My bottom line on all this is that Shane may well be the best Ten Ball player of this generation (with a lot of close competitors) and that's about all. He is not the most dominant player in any other pool game, just one of the best. He does have a great record in U.S. based events and has done well Internationally too. Buddy is the only player I can think of that was winning as many tournaments each year as Shane does now. He won them on 9' and bar tables just like Shane is doing today. And don't think his competition was not tough either, because it was, without having to name names of all the great players he had to deal with week after week. Remember, the U.S. had almost all the best players in the 70's, 80's and 90's when Buddy, Sigel, Nick and Earl ruled the game.
I'm with Stu here. GOAT, not hardly. Greatest American player of this era - definitely! He follows in the footsteps of Earl and Johnny leading up to today's group of American players. I will add this though. The current group of American pool players is the weakest I've ever seen. For many years we would have a couple dozen of the best players in the world in the USA. That's no longer the case and also why the Filipinos can come over here and clean house week after week.
P.S. the one huge blemish on Shane's resume remains his abysmal record in the Mosconi Cup. You can cut it any way you like but the fact remains he has failed over and over again to step up in this very important competition. The U.S. teams featuring Varner, Rempe, Davenport, Archer, Strickland and Morris wiped up the Euros year after year.