If Zelda isn't coming out at launch then it needs to perpetuate the strength of the launch cycle. What is really important is what Nintendo has planned for the rest of the launch period, which will likely "stress" the importance of localizing Zelda. For example, Nintendo has shown us that we can expect games like the fabled 3D Mario, Mario Kart, and Splat2n close to the Switch launch, and that's not even taking in the third party titles that could potentially be coming afterwards. However, I will agree that Zelda feels like a holiday title, and that both Mario Kart 8 and the original Splatoon launched prior to Summer. If Nintendo has the Switch versions of these games targeted around these same time periods, then that leaves a big Holiday spot open, unless they haven't revealed something they are planning to drop. However, Mario Kart 7 was released in December, so Mario Kart Switch could definitely fill that spot.
With many developers seemingly lacking access to Switch kits, I imagine a select few games will be targeted for the release window, among them being some poor-performance version of Skyrim, EA's "big title", a Dragon Quest or maybe even the first episode of Final Fantasy VII, and whatever Image and Form has cooked up- or maybe not, seeing as their development cycles are pretty long. With Nintendo's own releases being impressive powerhouses in their own right, I wonder where Zelda necessarily has to fit in the Switch's first year. Who knows, maybe it will slip into 2018.
As a burned Wii U owner and Switch skeptic, Zelda's slipping date is obviously aggravating, but it does pose an interesting question, one that I don't believe we have never faced- what happens to a "dual release" title if it's not being released close to the second console's launch? Does the previous version get screwed over? If the Switch fails miserably after its initial launch, does a dual release make sense in order to optimize sales? While these questions exist, the truth is, we have seen Breath of the Wild running on Wii U only, and so, I don't think they'll shelf its release. The more I think about it, it definitely makes sense to go digital, so that they can encourage a digital transfer to Switch when the sales begin to disappoint and the Wii U is dropped completely.