That's a BS reasons honestly. It shouldn't matter how many discs a game is on. If the game is good, then it stands up for itself.
And from the many hours I've played, it is a fantastic game. Changing discs has not been an issue for me, hasn't ruined any immersion etc.
Also, there was said to be double the content Bondi wanted to put on it, so 2 Blu-rays/6 discs. But that really would be too much. Lots of cases are coming in the form of DLC, and with that.. that's even more hours to put into the game.