Genuinely curious: do you think a `Synopsis.md` would be that much easier than the current system with a potentially long description in the .cabal file? I could see a case either way. Or maybe I'm just misunderstanding the distinction.
On the one hand, a separate file makes organization easier and markdown is a known quantity; on the other, it seems functionally equivalent to what we *can* do now albeit with Haddock syntax and in a file full of other details.
I could see why a file would be easier, and maybe that's enough to encourage more people to write one. We could even have .cabal just render the existing README file or something! On the other hand, that would take some effort and sometimes using Haddock markup and sometimes using markdown would be confusing.
Maybe we could have a guerrilla campaign of pull requests adding examples and a bit of explanation to every package you like that doesn't have them... That could also be a good way for beginners who want to contribute to start.