I think Kojima made it very clear in one of the interviews that He thinks that with this final installment of MGS, the fans want volume, more story,longer cutscenes and more Codec conversations(though it was seriously cut down this time).Atleast that is how he interpreted fans' expectations and that also justifies the way the cutscenes are in the game
It's obviously one of the biggest games this gen, and it is and will be a huge financial success. At the same time, I think the design is polarizing among the gaming community, because it really stresses the boundaries of what classifies as a video game.