One frustration that I have had while dabbling in Haskell is that some libraries in Hackage assume a GNU/Linux kind of system. For example, I was reading Simon Marlow's book and while trying to compile the examples in a Windows machine, a particular library could not be installed because of the lack of 'configure' (GNU autotools? I only use Windows nowadays due to professional reasons and have not used GNU/Linux last 11 years). I hope that library authors do not make such assumptions unless it really necessary.
Is there an opportunity for a company to create an implementation of Haskell which fixes some commonly mentioned problems (e.g. stop the world GC) - like proprietary JVM vendors? Is it even technically feasible? Of course, such a hypothetical company would also need to spend a lot of time writing useful libraries.