I do believe that there are times when you need to get the word out there as much as you can about a product, but I've also felt that there is a line where that marketing money is wasted.
AAA budgets have ballooned in size for various reasons as it is, and tbh I think we would be served by having the ratio of it spent on actual development : marketing related costs move more towards the former than the latter.
Eg in Halo 5's case, imagine if MS spent less money on trying to pitch us Chief vs Locke, and more on say, a level or some more cutscenes or earlier material to show Blue Team reuniting etc / wtf happened to the Didact (i know what happened, I'm just using it as an example)