This is some very upsetting news, or rather, lack of official news. The rerelease of the original DVDs for the 25th anniversary is one thing, I dont even have a blueray player and I will probably still buy it, but delaying a game for that period of time is nonsense. Considering marketing is not cheap, there is many ways that both situations (release on date, or anniversary) can work.
1. On Date: Release goes well, public purchases, target audience quickly adopts game, mass audience sees reviews, goes well, they pick it up. After completing the game, and enjoying it so much, people begin to think about the movies, and they really want to see them again, then rerelease in HD. This allows the game to be used as a for of marketing, it could even have a picture for the release on the back of the manual.
2. Anniversary: The date seems obviously more significant, core audience (Us.) appreciate the sentiment and new dvds are also released, with hardly any fanfare or demand. Marketing would have to be more aggressive, and chances are sales will be lower.
I cant think of any other big game coming out in October, it would be perfect time to release it, considering that I assume by anniversary they mean June 7th (or 8th depending on your belief of original release). Thats a prime time for game line ups, big summer blockbuster hits, it seems almost too foolish from a laymen's point a view, let alone from a corporate marketer.
A good person to ask is good old Danny Akroyd. I know that Ghostbuster's is his baby, and if this is as close as it gets to number 3, then I am sure he has something personal to say about it. God knows that if he had the money he would produce it.
Sony, if you are reading this, a great idea for the 25th anniversary would be for you to release a new Ghostbusters feature film in theaters. Now that a plan!