Will they ever make a masterpiece?
We can only hope.
They'll never make anything that surpasses Disappearance, so if you don't consider that a masterpiece (I think it's debatable, depends on how you define a masterpiece), then no.
Nichijou, Disapearance, K-On!! and Hyouka were masterpieces. Rephrase your question to "Will they ever make another masterpiece?" The answer to that is yes. Koe no Katashi and Violet Evergarden will be masterpieces, Hibike S2 has a high chance of being one as well.
Yes, but it had forced jiggle physics.
Now, if Kyoani had made Yuki-chan, that would be their masterpiece. It didn't have forced animation, ost and plot, and the characters and voice acting were way less forced than in Haruhi.
Thank you for saying this. Too many people put Disappearance on a pedestal when it's built on the foundation of a tremendously successful season 1 that was a cultural phenomenon years before the movie.