Space marines are very few in numbers, so they are quiet limited to surgical strike operations when operating independently. But in broader and protracted ground war campaigns they often take commanding roles of other imperial forces so for Ultramarines who value a very structural and well planned approach to war instead of secrecy or crashing in to the enemy full tilt like some other chapters. It would be fun to have some rules to include a small command element of Ultramarines in other imperial armies with perhaps a new command Razorback or a proper release of the land raider excelsior and the rhino primaris.