The biggest advantage the NX will have is that it will finally bring back all of Nintendo's developers under one roof. Even 3rd parties, even though they still are developing for an unconventional platform, only need to develop for one unconventional platform rather than 2. So the next Lego game doesn't need a 3DS version as well, it could just be on NX.
Also the next Pokemon after Sun and Moon will be on NX and you can play it on the go and at home on the same system, and before that wouldn't have counted as a release for those that only owned their home console. So they are more able to plug holes in their release schedule by combining handheld and home console.
Also hope they bet on the price. I'm going $249. I think they price this thing to move, and the specs I don't think will wow anyone. I think they are embracing the Nintendo game delivery device narrative and will be trying to get this into as many hands as possible to do that. The screen worries me though, and makes me think it may creep to $299.