I guess it all depends how much gameplay they were to show. They could do cinematic trailers and include gameplay that appears to be straightforward enough... just wet the appetite a bit for NX, get at least a little hype going for it, then announce the date the NX event will be..?
I dunno, I just think it's utterly insane for them to go into the biggest event in the industry with just one hands-on game and having nothing for NX.
Can't they really be that stupid?! Even for Nintendo that's daft.