In my opinion the feature Git has always been missing is version control of branches. Of course the immediate consequence would be that you'd be able to roll back changes to branches but there'd be some more fundamental consequences as well. I'm pretty sure some of the problems with GUI's/wrappers around Git break down because there's no tracking of branches/tags.
Besides that it's pretty much endgame in my opinion if you consider only the functionality it's meant to solve. If another "better" VCS would ever become popular I feel it would have to be a drastic change to the way of working with VCS, even more drastic than SVN to Git was. There's some cruft in Git that could probably be taken away, and that would make Git better in a theoretical sense, but in the real world that would never happen (unless we get sideswiped by another industry or platform).
Phabricator and Gerrit both do a really good job of this. To me Git works fine as a pure "version control" system, but the process of collaborating on a branch before it gets merged into a shared branch seems to be beyond the scope of version control -- something that a higher layer tool is ideal for.
Can you clarify what you mean by "version control of branches"? Branches in Git are just labels of objects. Are you talking about having a history of which objects a branch has previously labelled, like the reflog?
Yeah, I feel the reflog is more of a tool to do introspection on a git repository than that is a tool for collaboration. It's just something I've felt was missing from Git. If you're looking at the main branch of a repository, what was the previous version of that branch?
The way we work around that missing feature is by tagging commits so we don't forget what revision a release was made at for example. A sequence of release tags basically is a meta branch, a history of the release branch, but managed manually instead of through git.
Besides that it's pretty much endgame in my opinion if you consider only the functionality it's meant to solve. If another "better" VCS would ever become popular I feel it would have to be a drastic change to the way of working with VCS, even more drastic than SVN to Git was. There's some cruft in Git that could probably be taken away, and that would make Git better in a theoretical sense, but in the real world that would never happen (unless we get sideswiped by another industry or platform).