Having read a significant portion of the base WASM spec, it's really quite a beautiful format. It's well designed, clear, and very agnostic.

I particularly like how sectioned it is, which allows different functions to be preloaded/parsed/whatever independently.

It's not perfect by any means; I personally find it has too many instructions, and the block-based control flow is... strange. But it fills a great niche as a standard low-level isolated programming layer.