Historically I think Haskell will be very important as the substrate on which a lot of the next generation of dependently-typed languages (Idris, Agda) are bootstrapped on top of. It's a niche use admittedly, but it's hard to understate how great Haskell is for writing modern functional compilers.
Certainly possible. There's some great stuff going on there.
I actually think that clckwrks[0] cms could become it. Having a cms that is less buggy than those commonly used these days that can guarantee plugins being correct would be pretty huge.
Yeah, but both of those are command line tools. You don't have to know Haskell in order to use them. You don't even need to know that they are written in Haskell if your distro provides binary packages.
True, though pandoc exists as a library as well. Xmonad? Any of the web frameworks? That new rest framework? Shelly?