When Sony and Microsoft were APU shopping for the PS4 and XBO, it was a time when ARM didn't quite have 64 bit cores ready, which added obstacles to memory performance. Jaguar cores, at the time, were the best multi-purpose, little CPU cores available.
Today, that's no longer true. There's multiple 64bit ARM cores available, that would outperform AMD's Jaguar cores.... and Nvidia has capability to deliver an APU that would outperform the PS4 and XBO's APUs in pretty much all areas.... Such as CPU, GPU, and memory performance.
Intel could produce a superior to AMD console APU as well. They're able to put out 14nm chips already, and they can drop big amounts of really fast embedded memory on their APUs. Their X86 CPU performance is without rival, and what Intel may lack in GPU elegance, they can just make up for in raw transistor count.
This is going to sound a bit crazy, but there's a 3rd company that could also produce a superior APU to AMD. It's Samsung. Samsung is right up there with Intel in the bleeding edge of fab tech, they have engineers that can design powerful ARM CPU cores, and they have experience working with companies like Mali and PowerVR on custom SOCs. Do I think Samsung would be interested in making a console APU? Well, not really, BUT, they totally COULD if they wanted to, and they have the resources to produce a superior product than AMD.... and Samsung's memory technology could be a factor.
All that said, I have zero confidence in Nintendo with hardware at this point. I'm sure whatever decision they make, will be incredibly idiotic and disappointing.