From my conversation with the developer, they are trying to start the process for early access to the dev kit, the issue is getting through all the legal NDA stuff. Nintendo can't just release dev kits to any developer before they reveal the NX, I think it is too much of a lengthy process.
Nintendo key partners are most likely: Bandai Namco, Capcom, Square Enix, Sega, Altus, Activision (Skylanders), Warner Bros (Lego).
Makes sense to me to wait for the others to avoid too many leaks. You guys also need to consider Nintendo themselves will most likely have a strong launch line-up of possibly Smash Bros Ultimate, Zelda and a new Mario game.
If it becomes "open season" for all developers to order Dev Kits by May of this year, then the NX will probably be getting a healthy amount of ports from Third Party in the beginning through mid 2017.