Personally, I'd like to see:
- Far more of a focus on new microgames than older ones. Obviously WarioWare Gold was a best of setup, but yeah, it's the new stuff that gets me excited for each new game, not the repeats.
- Better souvenirs in general. Records were nice, and the mini game selection from WarioWare Gold can make for a good starting point too, but I'd generally like to see more of the wacky extras from Twisted/Touched rather than more alarm clocks and 3D models of video game systems.
- Some nicer animations and cutscenes would be good to see too. Don't get me wrong, I like the ones in Gold, but the voice acting doesn't always work well with the flash stylings of the cutscenes, and I think something closer to Wario Land Shake It or what not may work better for them in future.
- The return of the extra modes from Gold. Stuff like Sneaky Gamer and Wario Interrupts were nice extras, and I feel the Switch game should expand on that sort of thing with more interesting options.
- Maybe a few microgames that utilised the Switch's Joy-Cons. I mean, you can move them both separately, so why not increase the complexity of the motion controls to compensate?