Further entrenching this approach would likely run counter to efforts by testing-devex to stabilize a generic solution for test discovery, see Global Registration (a kind of pre-rfc)
While filling a different role than this thread, I've wondered about a more formal approach to dynamic linking in Rust. In the C++ world, you have headers-only libraries and dynamic libraries. Our static linking fills a role similar to headers-only libraries but we don't have something more akin to dynamic libraries. I could see us allowing a dependency sub-tree to be "independent" with its own lockfile and feature unification and could be built as a dynamic library for development builds (at least). By having its own lockfile, we'd also get better cross-project caching results with per-user caching.