At the very least I would have liked to see some kind of minimal global index of changes. With single-file vcs, you may have a large tree littered with .src files, and you have to walk to the whole tree just to find all your revision controlled files. By [also] storing them in a global index you could simply list all revision controlled files, then perform operations on them all or on parts of them, without having to 'find' each time. That could default to $HOME/.srcidx so you never have to initialize some root tree or track an environment variable.
