I'd love to see matte painting work competently in game. I've always been drawn to the idea of creating all special effects within blockland itself so that it feels natural (considering this is a sandbox game, I like using the sandbox to its fullest).
I have a post-Block-Wars idea in the works (between me and Camel) that would be an homage to the great epic classics that would benefit from using very old techniques. But then, considering how long Block Wars is taking, I'm skeptical of trying it because it'd be an even bigger production than that was lol.