The problem is timing and communication to hardcore as well as casual gamers.
Imagine you are Capcom, you have the brand new Monster Hunter World which finally can win over the West, and you have MHXX which is a Deluxe-edition of an existing title which targets the Japanese market and current western fans of the product.
Do you really want to announce those two at the same time and risk having a confusing message towards the market you finally want to appeal to? Capcom said no, the hardcore-fans are pissed, but casual fans now only have to remember the one game that is targeted towards them.
Then a couple of weeks later they can announce XX for the West, the fans will be happy, "Monster Hunter" will make another round through the news-cycle and Capcom can play the "we listen to the fans"-card.
Edit: this was meant to be in the "rough E3"-thread.