Yeah content was the biggest problem to over come if a new title were to come to Switch, I tried to list a few ideas that help expand the game but I'm still not sure it's enough to justify. The 3DS game felt very similar to the original, if they are going to do a non-mobile title they'll have to try and change that and do something new with the concept as best they can.
I think the main draw they'd go with is that, this would end up being a rare title were Nintendo tries to push realism and graphics first.
Tomodachi Life is another title I hope comes to Switch as well, but I'm greedy and want both
I guess they could treat it like The Order 1886, but price it a bit more fairly on release.
I think Nintendogs will come back at some point. Whether it will be developed as a budget title for $20-30 on Switch or some free-to-start app on mobile will be the question.