We don't need to go any further than here for the Alliance. Hereditary titles are a thing and were often associated with the military (i.e.: Shogun is likely one of the most well known). The only faction that might take issue with this would be the Night Elves, as the Dwarves, Gnomes, Void Elves, and Gilneans would all have longstanding ties with the Alliance (the Void Elves with the first Grand Alliance) and would understand the process, the Pandaren would not care, and the Draenei would probably be OK with it as Anduin has a close relationship with Velen.