I think less than 3DS, but it's hard to make any kind of definitive prediction on the basis of a 3 minute trailer with no info on price, other specific games, and many other issues.
3DS was a bit lucky in that it had a year or two where it didn't face the full brunt of damage from cheap tablets. When 3DS launched, iPad was basically the defacto tablet and it was expensive, only adults and really rich teenagers had them, but as tablets became so cheap that even little kids could have their own, we saw 3DS sales become stunted, and Switch (damnit keep wanting to say NX) is going to have to deal with that from day 1.
I think Nintendo has to allow Android apps somehow. Maybe not all of them, but at least the most popular ones. You can't ask kids to choose between their Android tablet and Switch. They love their apps and they aren't going to give those up, Nintendo has to be the one that bends, besides you can still make money off Android apps.
Not launching for Christmas is really regrettable, especially since from what I'm seeing from the hardware doesn't seem all that special. Really a wasted oppurtunity by Nintendo, March is a much shittier time to launch.