I'm all for flexibility, so long as it doesn't require too much
hackery to implement it.  You'll have two problems:

  * Determining what to commit.

    You'd have to have RCS keep a log of all versioned files it
    touched, and extend .commit() to accept the keyword list "files"
    and commit only those files.  This is doable, but maybe not worth
    the trouble.

  * Generating meaningful commit messages.

    You'd have to add this functionality to each command (and future
    commands).

This would probably not be a good idea for the Arch and Mercurial
backends, since they have a limited ability to rewrite history when
you screw up your commit message (as far as I can tell).  Mercurial
does have "hg rollback", but it only works once, and lots of
typo-correction commits would just make the logs awkward.