Yes, every crate using a different versions of their dependencies involves a lot more work for distros, especially when a crate uses a -sys crate (e.g. libgit2-sys) and libgit2-sys does an API break. Now every crate that uses libgit2-sys in the repo manually needs its dependencies updated, which is a rather time consuming process (especially if the bindings in libgit2-sys are only built against some random git version).