I'm not sure if it would help much. That means you either have to have users be able to recognize and eyeball-validate hashes ("sure, this is left-pad-5ffc991e; that's what I want! Wait, shit, it's actually left-pad-5ffd991e, never mind; wrong package), or you need pre-existing databases of trusted hashes (which either puts you right back at a registry a la NPM, or leaves you reliant on a package.lock file or similar, which doesn't cover many common use cases for secure package signing).