Let's say the next portable has a 720x480 resolution and the next home console is optimized to render that at 1080p with some high quality AA.
Why would Nintendo assume a 3:2 screen ratio if the initial render is done in 16:9?
4 core Puma, 4 CU GCN 2.0 GPU (4/500MHz or would that be too much?) would be insane for a handheld, although maybe I'm not looking far enough into the future.
I don't know about GCN 2.0, but assuming GCN 1.x proportions, 4 CUs at 500MHz would result in 256 Gflops.
In comparison, 5 months old Shield Tablet with Tegra K1 has its GK20A doing 384GFlops (or about 340GFlops at more "realistic" clocks), and the 2 month-old ipad air 2 with A8X is doing 240GFlops FP32 + 360GFlops FP16.
Given how we already have that kind of performance right now, a 4CU GCN GPU @500MHz in 2016 will be pretty mediocre. By then, I'm expecting Qualcomm's midranges (Snapdragon 4xx and 6xx) to be around that, to be honest.
If we were talking about a truly progressive hardware design, we'd need to look at the Vita's SoC in late 2011 compared to anything else. It bundled a SGX543MP4+ in December 2011, which was only surpassed by ipad 3's similar SGX543MP4 a few months later, and yet the Vita carried twice the Cortex A9 CPU cores and a TSV-ish memory configuration for increased memory bandwidth.
The Vita-equivalent of a powerful handheld in 2016 would have 6-8 GCN CUs at 800-1000MHz (high-end SoCs should be approaching 1TFlops by then), together with 6-8 CPU cores and HBM doing over 40GB/s.
And yes, this is biting on the toes of XBone's performance.
However, 4 GCN CUs at 500MHz is quite above of what I'd expect from Nintendo for a handheld SoC in 2016.
Heck, looking at the 3DS, they would probably pull it off with a 2 CU design at 250MHz and a dual-core Cortex A7 at 800MHz, using 28nm from GloFo.
People wouldn't stop at this from buying pokemon and mario, and that's as far as Nintendo can see.