Gretzky did save hockey by bringing in fans and getting people interested in it. When he became an LA King, it was a sad day for the Oilers but a great day for the health of hockey in California and the United States. Plus, by becoming a LA King, Gretzky sparked an interest in the game by children, which is now bearing fruit. Look at how many young players from the United States there are that are rated very high by the scouting agencies, like Phil Kessel and Erik Johnson.
I am against retiring numbers. I could see you raising the player's jersey into the rafters and celebrating him, but unless that player was one of the greatest to play then it shouldn't happen. The Blue Jays don't retire numbers, they put there players on a wall which is covered in the teams greats.