In his PRIME, how GREAT of a player was former Edmonton Oilers/Los Angeles Kings/New York Rangers Centre Wayne Gretzky?

He isn't called "The Great One" for nothing.  He's the only player to tally more than 200 points in a season, and he did it 4 times.  In his prime he consistently averaged more than 2 points per game.  Overall, if you counted only his assists, he'd still be at the top of the points list.  

he also played for the st. louis blues. he was the greatest nhl player ever.

Wayne was the best ever. Booby Boar was good but not as good as Wayne in my books.

This is the sort of question that's subjective and can be debated ad nauseum. Every hockey fan will have variations on who is the greatest player of all time. 

That being stated, IMHO, Gretz is among the top three players of all time.

For my money, Bobby Orr is the best player to have ever played the game of North American pro hockey, at any position.

Number Two? Vladislav Tretiak, the great Russian/Soviet goalie.

Gretz is Number Three. 

Again, just one man's subjective opinion.

There was no one like him, before or since. He won the Art Ross (overall scoring) 10 times and is the only player to score 200 or more points in a season - and he did it four times.   He scored more than 900 points for his career than the next player on the list and he did it in 246 fewer games.  He has more assists than ANY other player has points.

A dozen or so players scored more power play goals (and a couple of those, HE was the guy that set up a lot of them), but he has the lead, by far, in even-strength goals, and he is the all-time leader in short-handed goals.

Quite a few guys had more game-winning goals than he did, but no one is close to him in assists that set up game-winners.

He was the best of the best at his game, a verified legend in flesh and blood.  

Baseball had Babe Ruth, boxing had Muhammad Ali, British football had David Beckham, Kung Fu had Bruce Lee.  In hockey, the name is Wayne Gretzky.

He was so good that after he retired from the league, the NHL officially retired the number 99 forever.

Greatest player to play the position.

Among the all time greats in any sport. 

In hockey you get a point whether scoring a goal, or assisting on one. There were years 

during which he had more points on assists, would have won that without scoring a goal. 

Try imagining a baseball player with the most RBI's despite not hitting a single home run.

Same goes for career.. He has more assists than the #2 pointgetter has goals + assists.

He's one of the all-time greats of the NHL.

hopefully a pretty good playing