Thank you for the comment and feedback!
The goal of this project was to transplant Luigi from SMAS+SMW to the standalone version of SMW and create a sort of parallel universe were Luigi was the main character all along. A lot of effort was put into keeping as much as possible of the original game's logic intact and trying to make it seem like an officially released product. That's why I reused all memory addresses and replaced the original palette and graphics data instead of expanding the ROM size and putting all the new data there.
I hope that makes sense
Maybe I should put that in the description or readme.
So SMW:SMA2 physics is outside the scope of this project, but it's a cool idea! I personally didn't enjoy Luigi's physics and played with Luigi riding on Yoshi as much as possible
I do however love the extra content the Super Mario Advance-series added. Like the menu keeping track of your progress collecting dragon coins in SMW:SMA2 or the secret levels in YI:SMA3.
I'd love to see all the SMA2 features (including Luigi physics) backported onto SNES if that hasn't been done yet! It would be like a kind of Definite Edition with GBA-content and color/resolution/sound of the SNES. It would be a lot of work but if someone wants to collaborate on something like that, I'd be interested!
Another idea I had was to create checks and have the in-game text switch between Mario/Luigi depending on what character is actually in use. I'm currently looking into Virtual Boy Wario Land so I can't 100% promise I'll work on SMW anytime soon.