It is hard to say, I wonder what people predicted previous times when a new system came out what it's hypothetical successor specs would be.
I think the coming generation may be the hardest to predict. Using something like cloud computing seems far off now, but in six years time hard to say. I think what may hold systems back is the availability of such infrastructure. If I had to guess Sony's global foot print make them very aware that cannot go too far in a new direction without alienating much of its fan base.
My guess (and it is a guess) is a system with 64GB of ram, roughly 8GB reserved for OS and other functions.








