Kojima doesn't want to be deeply involved in Metal Gear Solid 5, wants to make a new game

"I think we'll probably have to make it at some point (Metal Gear Solid 5), but what that will be, we have no idea. As far as my involvement in the project is concerned, [it] probably won't be as much as it was with MGS1 -- maybe I can do just one stage! For MGS1 I made the maps myself, laid out the enemy routes myself, did everything hands-on -- that level I can't do again. I would like to just make a new game, and the younger staff can work on the new MGS projects. For MGS5, it's very difficult to explain right now because we haven't announced anything. I have really high expectations of my young staff, though. (I have) three concepts for MGS5 already. What would be ideal for me with MGS5, though, is that we don't do those. If the team picks one of those concepts, I have to get involved again, which I don't want to do. There are already so many good ideas from the staff, so if we select one of those, that would be really good. At that point I could really rely on them and take the step back to be the producer, which is the ideal situation, I think." - Hideo Kojima

I know Kojima hasn't exactly been ultra enthusiastic about working on the next Metal Gear game for quite some time, and it looks like he might be working on something new sometime soon.