First off, the announcement is great. We will finally have a chance to play with the greats and see how they match up against today's players. And to say that it is not an announcement that is big, let's look at basketball and football. 2K added Jordan and sold more copies than ever before. NFL allowed legends and 2K based an entire game on them.
Now, to be honest, outside of Canada these legends won't seem all that great, but to Canadians over 20, these are the guys we grew up idolizing and it will be great to play with them. I am going to reserve full judgement until I see how they are going to be incorporated, but I am excited. And to say this is the same as the All Canadiens team is garbage, these guys made hockey in North America a great sport, the Canadiens were important in Canada, but if you didn't like Montreal, you didn't like them. The NHL has a tougher time selling "Legends" because there are many "professional" leagues in the world, unlike the NFL and NBA.
I truly believe that the announcement that would change the way you played every mode was the new simulation thing. So I think people are confused that this is THE big announcement.
All that being said, I truly believe that more people are ecited about the game because of Gretzky being in it than TD Garden in Boston.