I think it'd be a good idea to start using a pretty printer! ansi-wl-pprint fits the task quite nicely.

Bonus points would be to use annotated-wl-pprint, and use the annotations to do the same thing that ansi-wl-pprint can do with coloring text and such. (I imagine those annotations would also make a good addition to that libary)

I'm imagining having some utility functions that allow you to do $logPretty, $logPrettyError, or $logPrettyWarn. When used, these would have the type (MonadLogger m, HasPrettyOptions env, MonadReader env m) => Doc -> m (). In other words, we need to be able to log the output and have pretty options to pass to the pretty printer. These changes would mostly happen in Stack.Types.StackT.