See also https://bugzilla.redhat.com/show_bug.cgi?id=1233429 The command `openstack overcloud scale stack` should accept the Tuskar plan as --plan and accept either the name or ID. The command should work without a Tuskar plan for users that want to scale a tripleo heat template deploy.
I am not sure if this is worth doing however, as see this bug also: https://bugzilla.redhat.com/show_bug.cgi?id=1233201
As there are now more general ways how to scale stack, the solution here would be to remove "openstack scale stack" command entirely instead of extending it, correct?
Yeah, that probably would be the best approach - and since it looks like you agree on the other bug we can close this one.