It seems like most recent speculation has been on the systems using two different ARM CPUs, If I'm not mistaken, the 3DS uses an old ARM CPU, but would it still be compatible? Basically, do we think that the NX (if it ran with an ARM processor) could run 3DS games natively through backwards compatible CPU architecture?
I'm somewhat interested in Fire Emblem Fates for example, but I'm wondering if the NX could possibly play 3DS games, because if so I'd rather get 3DS games digitally on whatever comes next. The 3DS is just a little too archaic to come back to from Vita for me, but playing 3DS games on a backwards compatible NX is much more appealing for the implied online infrastructure upgrades (like account ownership of digital games rather than them being tied to a console) and the possibility of bilinear filtering as an option.
On that note, with talk of "multiple devices" and not just two, could there be a console, a more traditional handheld with only one touch screen, and a handheld more similar to the DS & 3DS with a 3D screen (with face tracking) on the top and a touchscreen on the bottom?
At the very least, I think the customization focus with the New 3DS (faceplates) is likely to return in the NX handheld.
(Sorry that these are somewhat jumbled thoughts, I don't have a ton of time to post since I have to catch a bus soon.)