I think they'll go with 720 because they can put HD in the marketing. It won't cost very much and by fall 2016 it will be the equivalent of them being behind the curve when everything else is 1080p AMOLED, infinite PPI etc

Depends on the game ... my little Samsung tablet that's a bargain basement piece of sub $200 piece of tech can run games at 720p just fine. It won't run Far Cry 3 at 720p obviously but Sim City or Clash of Clans? Sure. Even a dated iPhone 5s chip, something Nintendo could have for peanuts could drive a 720p display with graphics considerably better than the Vita. 

Just because you have a 720p display doesn't mean every game has to run at 720p. I'm going to guess most people here have a 1080p TV ... well they've been playing sub-1080p games on their TVs for ages (shudders at the Wii era). When you play a Virtual Console game on 3DS from your DS you're running games at a lower resolution than the native screen. Ditto for GBA/SNES games on the Wii U tablet that look just fine. 

The 3D display on the 3DS is what's a huge battery/performance hog. Remove that and you can get a cheaper HD screen that's easy on battery life. No one cares about 3D these day anyways (you might want to write an actual story for Avatar 2, Mr. Cameron), and for those who do there's always a possibility to release a 3D version later (why not, Nintendo releases 3-4 different revisions of each handheld anyway, might as well have one that's tangiably different). 

The DS and 3DS weren't that far behind on the tech curve. It was just Sony went all out with the hardware in their handhelds, for some reason. 

GB ~ NES * , GBA ~ SNES *, NDS ~ N64 *, 3DS ~ Gamecube *, New 3DS ~ Wii *, Next Handheld ~ Wii U * sounds about right. This is especially true if we consider that the smartphone boom has made the hardware necessary quite cheap. 

* Some ways better and some ways worse. For ecample GBA was capable of better 3D rendering while SNES had better sound. NDS has higher resolution textures which were more detailed, while N64 had texture filtering and higher polygon counts (as well as a higher resolution.) 3DS is capable of better shading and overall features, while GC has higher geometry and better textures on average. Possibly most games will run at 540p anyway, to save resources for other things, even if the display was capable of 720p. 

If we are looking at a late 2016 release, then the necessary hardware would be more mid-end than high-end, which coincides with Nintendo's history of handheld development. 

Do you guys want a single or double screen? I think I honestly want a single screen, but I'm not entirely sure!

It will depend on how much it will cost to have a 720p display with parallax 3D tech with the face tracking. Cause trust me, they didn't develop that tech just to drop it in 2 years' time. Especially with the N3DS doing so well

I think it'll be 720p.

They can claim HD hardware which would help market it, and it won't be that expensive by the time they launch it. (late 2016 to early 2017 I think).

I wouldn't mind it that much though if it ends up 480p though. Wii U gamepad is 480p and looks good. The small screens compensate a lot, 3DS still looks fine to me.

I expect the next handheld games to look just as good as the Wii u gamepad screen which is 720 I believe.

Most likely, but i'm sure when 3D is on, it won't be in HD

Nintendo handheld always comes with low resolution not because of hardware cost but software development cost, this is how they earn their profits more than Sony...

Actually. it's 480p. 

Taken from here: http://wiiudaily.com/wii-u-gamepad/

• 6.2 inch touch screen with 854 x 480 resolution with stylus support