I disagree somewhat. Without Kojima there is no Metal Gear. I mean, yes, there could obviously be games with "Metal Gear" written on the box, and they could star a gruff guy with a bandanna, but what Metal Gear "is" is tied intrinsically with Hideo Kojima. He is one of the very tiny handful of actual auteurs in game development, and he's certainly the only auteur making games on the scale of Metal Gear. (Obviously Kojima isn't solely responsible for it. There have been other collaborators that helped make Metal Gear what it is, most notably Yoji Shinkawa. But those people will all be gone with Kojima by the end of the year.)
Now, I understand that there's a fairly sizable chunk of Metal Gear fans out there who lament the direction Kojima took the series in after MGS1, and they would much prefer "Tom Clancy's Metal Gear" for lack of a better term, to what we ended up getting. On a certain level I can understand that, because I used to think the same way when I was a teenager. And to be honest, I can only imagine we'll get something closer to that in the future, so good for you guys I guess.
However, make no mistake. Whatever becomes of the franchise after The Phantom Pain, good or bad, whether or not it appeals to each of our personal preferences, without someone with the ambition and artistic sensibilities of Hideo Kojima at the helm, I guarantee you it will be a wholly lesser series.