Yes, in some games, even those without paid and full ‘Switch 2 Edition’ upgrades, there will be noticeable improvements.
What do these improvements look like? In short, better resolutions, faster loading times and more stable game performance in the form of higher frame rates.
Example: a Switch 1 game you own is locked to 30fps (frames per second) but regularly drops to 20fps. Playing that same game on Switch 2 will result in it hitting 30fps most of the time (if not all). Of course, this will vary on a game-by-game basis.
Developers will be able to patch games if they choose. These patches are expected to be free. Nintendo will be patching select Switch 1 games for free, including Link’s Awakening.
GameChat will also be available for Switch games played on Switch 2. Even for previously released games.
Bottom line:
If you have a large Switch 1 library, you’re in for a good time!