In my opinion if you've come at a crossroads on how to deliver to the public, I'd recommend making a generic open source version that's flat, and a unique version to call your own and distribute both.
As far as what needs to go onto it?
cherry b

oms would be a great touch. If you could make a falling petal effect I think that would be even better. you could add in an ambiance brstm.
Is there some way to take the code from Yoshi's island (brawl) to make a night and day transition?