Interesting overview!

Some of this caveats are kinda surprising for me, coming from a Mercurial background:

* Every time you add a submodule, change its remote’s URL, or change the referenced commit for it, you demand a manual update by every collaborator. Forgetting this explicit update can result in silent regressions of the submodule’s referenced commit. -- This is something handled automatically in Mercurial. Is there any reason why the same behaviour is not used in Git?

* Commands such as status and diff display precious little info about submodules by default. -- This should be possible to implement, no? It's also something that's available in Mercurial (using the --subrepos flag), and it's a huge boost to usability.