I doubt Panda Express would go away for Super Nintendo World expansion (the land isn't really designed to go in that direction), but I do expect a new dining experience to go there in the next few years. I think they just needed a restaurant down there for capacity reasons. Now that Toadstool Cafe is open, it's no longer necessary.
I think the next 6 years will look like this:
2023: Super Nintendo World
2024: Fast & Furious Hollywood Drift, new Super Nintendo World mini-games
2025: New Studio Tour attraction to replace Supercharged, new restaurant to replace Panda Express
2026: Donkey Kong Country expansion for Super Nintendo World
2027: New DreamWorks Theatre film (maybe Shrek 5 themed?)
2028: London Expansion for Lower Lot, replacing Revenge of the Mummy. Ministry of Magic gets cloned instead of Escape from Gringotts.