Assuming the Hapsburgs don't get Spain, and so his death is butterflied away. I know Maximilian was trying to reorganize the Empire's government, but died before it was completed, and Charles never had the time to invest in Imperial reforms. By the time the Hapsburgs were able to pay attention to the Empire, the Protestant reformation had killed any chance at Imperial unity. Could a more attentive ruler have reformed the Empire into something resembling the more centralized states of France and England, or at the very least less of a clusterfuck?