The biggest reason I'm looking forward to a new version of Minecraft PTC is because the original, after years of programming it on the side, it still ran around 4-6 fps. With the running speed confirmed to be over 28 times faster, and sprite resizing being integrated into the language, it could look better and run faster.
My suggestion is learn how to use the commands PRINT and IF, then move on to using variables and rendering sprites. (I actually have little experience with SmileBASIC, but understand programming languages enough to start you up.) Never forget that you have the vast Internet in your hands if you want to learn something. At the very least, have fun exploring programming.
I remember hearing that the syntax of some commands were changed, so that may be a deal breaker for a few ports. I'm sure plenty of dedicated fans will do it for the creators if the creators themselves don't.
It's possible, but it will take you longer than you expect. I encourage you to at least try programming to see if you enjoy it, but it's not for everyone.
I agree with you on that QR code idea and backwards compatibility. Petit Computer is no longer available on the eShop, so all of the old projects are completely dead.