If it's a handheld, Japan will love it. And it will sell on the west to those who like handhelds better. So it does have an audience.

The big question for me is will DQ XI be the 3DS version on NX or the PS4 version. Probably I will be getting the game on PS4. But the Luigi's Mansion rumored game will be a Nintendo exclusive and a system seller must have for me. The NX will thrive on Nintendo exclusive games mostly as far as I'm concerned. That's why I'm excited for it.

PS4 still has a relatively low adoption in Japan, like 3 million or so? Even the Vita and Wii U have about that number, 3 million is nothing to write home about.

It's likely NX in Japan at least will overtake that quickly, it's quite possible the PS4 version of DQXI in Japan could actually be the lowest selling version. 

I'm you're talking about one system that is 1.) portable (we know Japan vastly prefers portable systems) 2.) will have ALL Nintendo IP, that means Pokemon AND Splatoon AND Animal Crossing AND Mario Kart in one place 3.) Probably also will continue to have Monster Hunter and Yokai Watch 4.) And will have Dragon Quest too. 5.) May have Android apps. 

Such a system is likely to sell quickly in Japan at least. 

Exactly! In Japan the NX will be THE system, with no serious competition from Sony or Microsoft. Here in the US, people prefer gaming on home consoles so the NX wont be as popular here, but will still sell really well because of Nintendo's exclusive games. Dragon's Quest fans may op for the version that they can play at home AND take on the go to play when and where they are. Some kind of multi-player hand held gameplay could sway me to by the NX version.

Now that would be exciting si long as its released in NA

Will Dragon quest be released on the NX in NA? Have they said either way?