Retaliate is already pushing the power curve, in my opinion. It's probably as good as Bear Strength. When I force-ranked Gurmash's commands, in my opinion, Retaliate would have been the best, and by a wide enough margin that Gurmash would have become something of a one-trick-pony in competitive play.
Now, that's just one playtester's opinion, but I found that Gurmash is at his most powerful with the Enchantment commands because they're often useful right away. All the other familiars can cast spells that are useful immediately (Force Hammer, Teleport, Enfeeble) but as a tradeoff for his durability, Gurmash is a bit more limited. Many commands have tricky timing when they're cast by Gurmash instead of your mage's Quickcast: if you have him cast Battle Fury, for example, your opponent may get a creature activation before you can use the Commanded creature. Your opponent can then retreat or guard or otherwise make your optimal use of Battle Fury difficult.
But the Enchantment commands largely avoid this problem, because they're ready to be revealed as soon as your opponent takes his next creature action. The armor from Fortified Position, or Standard Bearer can apply immediately. But the best enchantment command in the game would be Retaliate, if Retaliate were a command. If Bloodwave Warlord gets his hands on a weapon, giving him counterstrike every turn for 6 turns basically shuts down any agro attempt.