I don't think the CPU part is equivalent to PS360 by quite a stretch. Maybe the GPU is in situations involving only light pixel shading and mostly opaque pixels (due to its tile-based deferred rendering scheme). It could certainly not match 360 fillrate in particular for transparent pixels...Apple A6. Believe.
The extra cost of the A8 K, an FM1 mobo, high speed RAM, and the risk of OCing it makes the example kind of moot.
I doubt it, unless the CPU is 3-4x faster than A5X CPU (and even more in vector processing). Quad core A15 based CPU could be 3x faster than the current dual core Cortex A9 (1.5x perf per core, 2x cores), but so far it seems that the first Krait and A15 based products will be dual cores. Maybe we will see a quad core A15 in A7. With second gen Rogue in it, it would likely reach current generation console performance (9 year behind them in time, but in your pocket).Apple A6. Believe.
Somehow I don't think that needing a motherboard (or 1866 RAM) counts as an extra cost! (especially when the OP has not said a thing about price).
You're still having to sink extra cost into an 'unlocked' processor, an FM1 mobo (which can be very expensive compared to the last gen of AM3s) and possibly very fast memory to get the most out of it. While I am a fan of Fusion, at the same time, to me it's worthless as a serious desktop platform for gaming. Mobile is a different argument, but on the desktop front, Fusion is a bit silly as a gaming platform, and we'll probably never see Fusion APUs get used for GPGPU game physics. The best chance for that is use in a game console (suspected PS4?).
sure you could get a pentium G, lower end mobo, slower memory and a radeon 6850, stock heatsinks, so the APU is moot if you're after framerates.
piledriver APU will be incrementally better except it's on a FM2 socket, which I don't remember what's it for. fine grained "turbo", maybe.