So, if Nintendo was to make a SNES Mini 2, I’d like it to be pretty much the same as before with a bunch of classic SNES digital titles pre-installed, although maybe with the SNES Jr. model this time to easily differentiate it from the first one (I guess):
Along with one major addition, which would be a working [mini] cartridge slot that actually takes [mini] compilation carts of classic SNES games in a similar vain to the Evercade VS: https://evercade.co.uk/vs/
This would mean publishers like Nintendo, Capcom, Konami, Square-Enix, Namco, Atari, etc, could release their own compilation carts of classic SNES games in modern times and possibly even make some brand new games for it too.
And, in an ideal world, Nintendo would actually release proper development documentation, finally, and maybe even some kind of simple and very user-friendly software developement tools to go along with this, so indie developers could also build their own SNES Mini titles relatively easily too, which could be via a website or even built into the system directly in a similar vain to the Pico-8: https://www.lexaloffle.com/pico-8.php
At the bare minimun though, just having a working [mini] cartridge slot allowing additional physical [mini] games to be plugged in could be a game-changer in the Mini category imo.
I think that could take a new SNES Mini 2 from being another cool little stocking filler to something potentially very special, and maybe even give birth to a modern SNES Mini console/game market category in its own right.
Note: An important caveat here is that I think any new games made for the SNES Mini 2 should technically work on the original SNES system and within its limitations too, so these new games could also be released in large cartridge size for the normal SNES as well.