I gave up WSL after experiencing significant performance drop on GHC, Stackage. It was less than 1/10th of native for compiling Haskell code.
benhills describes the cause:
For some context, I've looked at what causes this slowdown. For some reason stack has mapped an mind-bogglingly huge region of memory (I'm talking dozens of terabytes). When we fork we walk the entire address range to set up the new process's state. We have a design that should vastly speed this up, but we're approaching "pencils down" date for Creators Update.