Metal Gear Rising might not be the only game in production at the moment with the words "Metal Gear" in the title, as the upcoming Official Playstation Magazine - UK reveals, though
If I had to guess, I'd say that "Project Ogre", whatever it is, is his first FOX Engine game made primarily for PS3 and Vita, though what it'll entail or revolve around is probably more up in the air than anything else could be. If anything's clear about anything, it's that Kojima will make what he wants which is something to be commended, yet also means that it's impossible to really predict. Between Metal Gear Solid, Policenauts, Snatcher, Boktai and his work with Castlevania: Lords of Shadow, it's clear that he's got a -lot- of range, so you can't even narrow down the possibilities. Whatever it is, it'll be distinctly Kojima and that's about all you can say for it beforehand.
As far as what Metal Gear Solid 5 is going to be, well.....that too is also as up in the air as anything could be. I was under the impression (as I figure many others were as well) that Metal Gear Solid 4 would be the end of Solid Snake's story, which despite Peace Walker originally being branded as Metal Gear Solid 5, still makes sense. As such with what's said about 4, I was also under the impression that Metal Gear Rising would be the Raiden answer to MGS, so a "Metal Gear 5" wasn't entirely necessary. Thus with those two characters both (theoretically) tied up, does this mean another run for Big Boss? There's still a lot of ground that can be covered with him, but I'm not really sure if I want another Big Boss game. I mean, yes, I do, but I just feel like his explained story is good enough.
It's kind of another God of War 4 situation in that there's really no reason to continue the branding with any of the existing characters, yet to make a new character would undermine the reason for making it another notch in the continuity. I just don't see a reason for Metal Gear Solid 5 in that I want another Metal Gear Solid game, but I don't want it called Metal Gear Solid. Rising is fine enough, it's its own entity and has its place in continuity but you know that it's going to be an entirely different game. As I imagine MGS5 just might be unless they (unfortunately) find a way to shoehorn another adventure of Solid Snake or Big Boss into the timeline which, I only say unfortunately because I imagine doing so will do more harm than good.
It's kind of like the difference between what I want and what I know what's 'responsible' and I want more Solid Snake and Big Boss, but I know it's not likely a good idea for more. I think that's the point that I'm trying to make here and I mean, at the end of the day it's all just games so it's not like it's going to 'undermine' anything, including itself, by hashing out. The most likely scenario for Metal Gear Solid 5 that I can see (without a new main character) is that it takes place as Big Boss right after Peace Walker and has the player setting up Outer Heaven proper which would probably rock out loud. Even moreso if they go the extra mile and re-imagine Metal Gear 1, placing you into the boots of Solid Snake for the 'second act' as it were. It would be awesome but wholly unnecessary narrative-wise since it just sets up a 'second beginning' for a character that was closed up fairly well enough.
But I would buy twelve copies is what I'm getting at, here.
Update!: So, I guess this is all kind of unconfirmed as Joystiq had another article about this that suggests they did not, in fact, read the magazine that had the bold declaration on the cover before reporting on it. Which is just fantastic, of course. But basically, it states that Kojima says "We'll -probably- have to make MGS5 sometime" and that if/when that time comes, he would like to be involved, but not at the helm. As he's said a few times now. So, there's that, I guess. GJ Joystiq.