Nintendo doesn't release big games like that in the summer. They prefer late May/ early June, or they wait until late August.
I would say that the July delay is probably just an expectation of many retailers assuming a delay, but that truthfully, if Star Fox Zero is delayed past April, I'd say that means it's being held back as a hybrid Wii U/ NX launch title for the holiday.
Given how unfavorably the game has been received ever since E3 2015, I doubt many would be disappointed. Delayed games are always better when they finally come out, it gives the game an extra six months of development time, and it gives the new console one of (hopefully) several high-profile launch titles. Wii U had a terrible, terrible launch lineup.
Launch NX with Star Fox, a new 3D Mario, and Zelda U, and NX will have by far the strongest launch lineup of any Nintendo system.
The Screamapillar is easily identified by its constant screaming—it even screams in its sleep. The Screamapillar is the favorite food of everything, is sexually attracted to fire, and needs constant reassurance or it will die.
