Sean Monahan
Brayden Schenn
Joe Pavelski
Jeff Carter
Steven Stamkos
Eric Staal
Patrick Marleau
None of these are centers who would be the best center on a legitimate championship contender. Maybe Stamkos, if he could score 60 goals again, but even then he's not the player he used to be back then. And no, Staal wasn't a better centre than Rod Brind'Amour in 06. That was just the year powerplays were inflated beyond belief and Staal benefitted immensely.
It's a consistent pattern for two reasons:
1) Because volume goal scorers will inevitably see some of their goals as so-called "GWG"s. That's how probability works. No one is denying that Monahan is a volume goal scorer. But his volume goal scoring, much like Stamkos and Carter on that list, is insufficient relative to his lack of a complete game. Just as Carter was at his best on Mike Richards' wing and Stamkos at his best (in terms of a deep playoff run) on Filpulla's wing, these are not ideal centremen, never mind number one centers.
2) Because Monahan's "sneak into open areas" style is more effective against defensively poor teams - teams that are easier to win against. It stands to reason that he would have more goals against bottom feeders - and thus more "GWG".
My contention is that three of those guys are wingers, and the other of those guys has four Selke trophies to add to four more top three finishes in Selke voting. So a metric that cannot differentiate wingers from centres is of no value in evaluating centres.
Ah yes, obscure stats like watching the game.
Um, the Flames have "won" nothing with Monahan as their number one center. They won one playoff series back in 2015 where Hartley coached circles around Desjardins, Brodie channelled his inner Scott Neidermayer, and Hiller stood on his head while Monahan's line was invisible until the final game. They've missed the playoffs in Monahan's first year, his third year, and his fifth year. They barely squeaked into the playoffs in Monahan's second year, his fourth year, and his seventh year. They finished tops in the conference once, when Monahan had as many "game winning goals" as NHL Superstar Garnet Hathaway, and then proceeded to lose in the first round. Monahan's never in his entire career been the most valuable center in a playoff series, and never will be. Heck, his current coach even seems to have figured out that he's better off using Monahan as a winger.