Gus definitely had me enrapt in his story as the lone leader of a group of bedraggled reserve soldiers, women, and children. A lot of it all came down to whether he could convince a dragon to do what he wanted, which, in the end, never really happened. It all came down to him learning what moved a dragon and then compromising with it.
It was nothing like what the Milan prince had tried to push Gus to do. He truly controlled the dragons by manipulation and sheer force. The heft of his mind magic was apparently truly terrifying.