the other racial leaders call anduin "my king"So, is our issue that there is a leader for the Alliance at all, or that leader being Anduin? I'm just asking because 90% of the time I see people complaining about the Alliance being an alliance, they were complaining that there shouldn't be a leader - which is wrong, as I brought up EU as an example (or many other alliances throughout the history). An alliance, even though its members will be treated equally, can still have a leader who act as the binding force for the rest. That's the current "High King" role (formerly "High Commander"). Anduin isn't literally king of the Alliance in the sense that he can lord over other leaders, and other leaders can in fact ignore Anduin / the High King if they want to.
Now, if the issue is that the figurehead leader role is taken Anduin, then I'd like to point out that it isn't too strange either. Anduin inherited the position of King of Stormwind from his father. Humans, as stated by Blizzard, is by far the most populated and powerful faction inside the Alliance - that's a plus. Anduin is also favored by a number of the Alliance leaders - Genn, Velen, Moira and Magni (might not be counted any longer now he's taken a more neutral role). Aysa didn't have any direct interaction with Anduin, but the Pandaren viewed him favorably as well due to his conducts in MoP. The other two leaders (Tyrande and Merkatoque) don't have anything against Anduin or the Humans either, as both were helped by them during Varian's time. With all that said, is it so weird that the Alliance leaders either wouldn't mind Anduin taking the High King role, or even support him for it?