-First, and most important: to know what the thing is.
-Second, no mandatory fee for online multiplayer.
-Third, not being more expensive than 400€
-Fourth, the promise of an unified platform. That would mean the NX would get a mainline Pokemon, and that is a must. If it doesn't, I'll just get the handheld.
-Fifth, a clear lineup of games. The WiiU had a lot of promises the first year, from both Nintendo and 3rd parties. Need to see all of them will fulfill their promises.