Indeed. Looked at that, even went so far as to give Datomic a tryout. Everything with built-in versioning turned out to be a leaky abstraction wrt our needs. Turns out there are lots of ways people can think about versioning, that don't always correspond to how programmers think about it.

For joining vcs (git) plus db (datomic), there's an interesting library called codeq: http://blog.datomic.com/2012/10/codeq.html?m=1