I doubted that Nintendo would say anything, just because this is so bad a venue for doing so. And "we will reveal the hardware this fiscal, and this is our software plan for the holiday" is about as good as you'd expect to get anyway, and they've already given investors (and us) that.
That said, I wouldn't be surprised by almost any window for the launch announcement. There is no perfect timing - if they want to make money off the Switch, they need to keep releasing games. And if they keep releasing games, there will never be a marketing free window for the new hardware to step into. The "best" window will entirely depend on stuff in Nintendo's pocket they haven't revealed.
I think folks expecting a September/October reveal might be getting ahead of themselves. Nintendo did a two stage reveal last time, showing the concept of their new hardware in order to get that into players minds, and then deep dive on the hardware and the library in January. They needed to show us the hardware but also convince us the bad old days of software droughts were over.
They don't need to do that anymore. Nintendo's reputation is totally different, and whatever New Stuff is in the next Switch, it's still a Switch. Instead of an October reveal and a January blowout, they could just do a January presentation, and leave the holiday season free from Switch 2 marketing. Not saying they will do that, but that it's not unreasonable, even for a March release.