I don't think that's true. I think he's appropriately appreciated and rated.
He will be remembered as a player that always left you wanting more, he leaves too much on the table.
Even the responses from the stans to those who are critical never really directly rebut the criticism.
He doesn't use his speed or size, yeah but he scores goals.
He handles the puck like a hand grenade, yeah but he's statistically good at 5v5.
None of those actually answer the criticisms, at least @Phil is honest and says he just doesn't care about the shortcomings.
Nobody's knocking the guy as a goal scorer. But a lot of people can see he's capable of much more.
So yeah, when I see that he has the most playoff goals for a Ranger, the first thing that comes to mind is that he could easily have many more if he utilized his skill set to its fullest potential.