I kind of want the next GT to come out as a full game for the next system. They need to work on higher fidelity all the way around. So keeping the graphics we have with premium cars, more or less, should allow them to focus on creating a fuller package around it. I'm talking about them keeping a consistent 60 (for real this time) frames, having a more complex structural geometry for the cars and tires running so that the physics are much more improved and especially allowing many more cars on track at the same time.
So them promising that, with a more robust online component ('cause let's face it, we're going in that direction of focus much more these days anyway), will make me quite happy in waiting maybe three or four years for a proper GT successor.
In my opinion I think there still will be something coming toward the end of the PS3's life cycle with the GT name on it, and it'll be something like a Prologue, but not - since Prologues usually come out on the same system the true successor releases on.
I'm thinking what's coming is a whole huge addition/expansion to GT5 that'll be the price of a full game. A slew of new tracks and cars (this is what I believe they're holding out on all the updated old tracks for as well) with the cars all being premiums, I'm guessing somewhere in the range of a few hundred new cars/updated standards.
This could also increase the online side of things as well, maybe bring new physics capabilities and various optimizations/upgrades all in one package. Basically, everything GT5 was supposed to be.
It would make sense because while they do that it could also be a build up toward GT6 at the same time, they could even spend extra time on all the cars making an extra detailed version of them ready for PS4 specifications along with a compressed PS3 ready version set to be used in the next game. So looking at it from a workphase sort of approach, it could be a clever way of being able to continue to push out a smaller product to make us happy while at the same time building the base for the next big true sequel in the game's franchise for the next generation of consoles to avoid the long wait we had to suffer between GT4 and 5.
All pure speculation anyway.