They stuffed it up with the Wii U console.
With the original Wii they captured the casual market and sold ten's of millions of consoles, it was one of the greatest success in gaming history. With the Wii U they un-did all of that great work.
One thing they can do is try to attract third party developers but they is going to be extremely hard with the failure of the Wii U plus there isn't going to be an established installer base.
Another thing they can try and do is to incorporate their smartphones apps with the new console somehow.
Personally, to me Nintendo is a one trick pony. Their business model basically revolves around releasing a mid strength console every four years a developing the same franchise games to gamers who bought the NES 25-30 years ago.
The only problem is that, that market has grown up and have jobs and families and probably aren't going to care to buy a new consoles just to play Zelda 8, Mario Party 13, Star Fox 5, Pokemon 10, Mario 35 etc etc.
Nintendo Wii = Sega MegaDrive/Genesis (Great sucess)
Nintendo Will U = Sega Saturn (mostly a failure)
Nintendo NX = Sega Dreamcast(Valiant last ditch attempt at gaming relevance again)
RIP Nintendo consoles
