If that is your view, you can't GM the BW game under discussion. This would come out in the preplay, when you made it clear to the player in question that you weren't prepared to run a game in which certain theories of monarchy were not taken as given."True King" is not vaguely defined. To be the true king, you must be by the laws of nature and man the one who is king.
For an account of the conceptual space in which views about "true kingship" can become more open, and hence the game becomes playable, see my lengthy response to [MENTION=6681948]N'raac[/MENTION].
As to whether BW is No Myth, it is not fully No Myth - the game has backstory - but it is No Myth to a high degree, as the game mechanics like Wises and Circles only work if backstory starts very loose and open ready to be filled in play; and resolution of failures per "Intent and Task" also requirs a very loose backstory at the start that is filled in via play.
That filling in of backstory is also part of what drives the game towards culmination - as the backstory is filled in, the room to move (both for participants at the table, and hence for PCs in the fictin) becomes less, the stakes therefore become higher (there is less and less room in front of you in which to "fail forward") and we can see the endgame approaching.
4e builds up the same story pressure in quite a different way - by adapting the traditional D&D idea of levelling into a combination of pacing mechanic and story scaling mechanic: as you level, the story is no longer about dealing with kobolds, but dealing with Tiamat - and when you deal with Tiamat again there is not much room in the fiction to "fail forward"! Of course you could reskin 4e so that epic level critters were still mere mortal, worldly entities - 4e Dark Sun does that to some degree. My own view is that this waters down the game, though - not fatally, but noticeably. Intead of having a story meaning, level at that point is simply an index of greater PC complexity. Given the effects of the level scaling on success probabilities (ie they basically don't change), it becomes more-or-less a functional variant of E6.