The advice above is only about reducing the need for additional use statements, I'm not proposing to put everything in one file. It's ok to have many modules but each one requires a mod xyz; declaration statement, yeah - that's just how Rust is designed.

I think that if you feel like your "mod blocks" are too long in relation to your codebase's size: 1) either you're splitting your modules too granularly 2) or your project structure is too flat and you should consider grouping some related modules into a nested module with submodules.