In Mercurial , revision numbers are local-clone specific, and they are provided as a facility to point to a specific changeset in a more user-friendly way than a changeset i
It is possible to reorder your repository (that's what contrib/shrink-revlog.py does). But in this case it seems overkill and complicated.
Since this is mostly a display issue, you should instead ask THG to implement the reordering you would like to have. I admittedly have no idea what you find messed up in the graph above.