I think it is fine if the promoted drunk elephant is not royal!
Indeed, then it would just be another piece, not very different in use from a Gold General. (In normal play it is mostly the forward power of a piece that counts.) But in the presented variant it is explicitly mentioned that the Crown Prince is royal. And that is pretty much a fatal flaw.
Indeed, then it would just be another piece, not very different in use from a Gold General. (In normal play it is mostly the forward power of a piece that counts.) But in the presented variant it is explicitly mentioned that the Crown Prince is royal. And that is pretty much a fatal flaw.