Sure it would be nice to have types for refactoring, but a more useful set of features would be:

- baked in fetchurl, fetchgit for easier bootstrapping

- a functional dsl for rendering filesystem hierarchies - instead of the find/sed/awk galore. 50% of the time when my nix recipe breaks it's not a nix syntax issue but something with bash. (reading nix is an exercise in learning new unix features)

- drop the channel feature entirely and make releases immutable tar files with hashes. I use nix as a build system on macos and right now a nix-channel update is a sure way to break all my builds which is the opposite of nix's promise

EDIT: formatting