Resident Evil leaker EvilVR on Twitter made a comment a while back about how Capcom has plans to port Resident Evil 7, 2, and 3 to the Switch, but only when the Switch is powerful enough. Now recently, it has been discovered that there are files in the Resident Evil 3 demo that suggest it was being worked on for the Switch. This makes me think there will indeed be a stronger version of the Switch, possibly this year, as they'd want to be able to compete with the next gen consoles and could even promote upcoming games like Breath of the Wild 2 and Metroid Prime 4 with it and even bundle them with consoles. Not just that, but a Borderlands collection was just announced for the Switch and while I'm sure the Switch can't handle Borderlands 3, it does seem suspicious that they would release all the other titles with no plans to release the third, unless they know there will be a stronger Switch coming that would allow Borderlands 3 to run properly...
With that said, I don't think backwards compatibility will ever be thing with Nintendo as they like to make unique hardware and keep switching the kind of media they store their games on. At the very least, I can see an entirely brand new console being backwards compatible with the Switch, but I don't see them ever getting their act together enough to make the kind of moves that Xbox has been making with their backwards compatibility because Nintendo likes to live in their own bubble and do things differently to a fault.