please let your business partner know that a command set will sell at least as well as the previous roman sets, because everyone having soldiers will need officers. And then, there will be those buying the officers AND the previous sets, because they were waiting for the officers. Thus, I really don't understand why this set hasn't been done yet. Assuming that financial interest is the motivation of your company.
I haven't yet heard of 4x4 drive car manufacturers hoping to sell cars with only 3 tyres.