What I like about this command is that it can be cast for free on an orc butcher with gurmesh's channeling or command ring discount. In addition, it can be reused, via helm of command. The butchers have a 4 dice attack, which isn't weak. A free guard on them is powerful.
I think a new theme of the warlord is alternate between low cost commands and large cost spells like conquer or summoning thorg.