I have a feeling they’re probably not going to drop the DS line. For one thing the Switch, while a great console, isn’t really the kind of durable handheld that Nintendo is known for. Admittedly the 3DS isn’t either compared to the Gameboy line, but it’s still much more durable than mobile phones or the erstwhile PSP line (which is worth having for Persona 1-4 and Growlanser IV, but not much else). Then again, the truth is I want them to keep making DS style systems, I’ve come to love the duel screen functionality, particularly with games like Etrian Odyssey, which wouldn’t work nearly as well on a single screen system, particularly one like the Switch where the touch screen interface isn’t even available if you’re playing it on the TV. My point is I love playing my Switch around the house, I even got a little carrying case for it for when it’s going walkies away from the TV. But I don’t really think of it as a handheld system the way I think of my 3DS, and it’s definitely not leaving my house the way my 3DS does.
I keep having the feeling that at E3 either this year or next year Nintendo will probably be announcing a new dedicated handheld system, one that will take the ideas that have become popular in the DS/3DS and improve on them. And also does screenshots without Miiverse. I NEED some sort of 3DS screenshotting program Nintendo! At least modify the Miiverse button our 3DS’s still have so they can save screenshots to our SD cards.