What I think they'll do is, have more or less 100% backwards compatibility, but with no improvements for any games, and then they'll probably try to sell upgraded versions of a few games, like the Zeldas or Smash Ultimates and such.
What I want them to do is have full backwards compatibility with free upgrades for as many games as possible. Which extends to my wider belief that when you buy a game, you should own it - on every platform it's on, period. But that's a topic for another day.