Looks fine to me, but patch didn't apply cleanly to the trunk (TracDev/SubmittingPatches). It will need unit tests before we can commit the changes.
We could also add TracAdminrename and reparent commands. Or maybe combine them in a single move <realm:id> <name> <new_realm:new_id> <new_name> command. We should also consider whether rename and reparent should be combined in a single method, adding an optional filename argument to reparent and possibly renaming the method to move.