“Since performance”? What’s wrong with the roof?
There is no such thing as “being finicky.” Your build is what you make it. You must orient it to represent what you want it to be. To be fussy about what you build is normal; to be slothful and generic about it is both unpleasing and unwanted. You have shown to me that you are dedicated to building, so don’t let that feeling blind you at all.
So far, I’ve been under the impression that it was meant to look cartoony due to the lack of material or textures. This is understandable. Personally, I believe the sliding would look okay with wood so long as a 80%–90% transparent gradient was applied to the bottom of each panel (so that it didn’t look bland).
Experiment with it, as you’ve said. Rome wasn’t built in a day, and neither was anybody’s building style.