Well, you have set the bar pretty high, Watch_dogs are supposedly the best selling new IP game EVER sitting at 4 million first week sale I believe... but you are also right, if Activision spent half a billion $ on the game, they must expect crazy sales numbers!
I don't think there has been any real buzz around it, I personally think it would have been better with a proper single player campaign + MP mode .. I don't like MMOs, they're too time consuming, I just don't have time for this much gaming anymore! and nobody should, it will kill you to sit that much, you need to go out and move!
Seriously, if you see the amound of discussion the Uncharted 4 teaser generated with barely nothing about the game compared to ALL of the Destiny promotion... ouch! and Destiny had real gameplay at the very beginning of the Sony conference, it has been heavily promoted for over a year now, people played it, etc.