I'm actually not really that concerned about NX's software library at all. It wouldn't surprise me much if it has one of the better 1st year lineups for a Nintendo system ever. Lets look at 3 reasons.
1.) Unifying the library will channel all their dev teams onto one platform, Nintendo releases like 20+ games per year, and usually at least 2/3 of those are of a fairly good quality.
2.) Because the NX doesn't appear to be a full generation upgrade from Wii U, but more like a portable Wii U++, Nintendo's developers are going to be able to get the hang of developing on the NX fairly easily if we're talking a Tegra X1 tier chip. They're just now getting into the swing of making HD Wii U games, the transition to the NX will be easy for them.
3.) Lets be honest, likely a lot of Wii U development was curbed/nixed in favor of the NX. Not just Zelda, we're probably talking a "real" Animal Crossing, another 3D Mario platformer, a second Retro Studios game, etc. that were supposed to be on the Wii U that got diverted to the NX a while ago. These games as a result will end up showing up early in the NX life cycle because Nintendo pulled resources from the Wii U a while ago.