I feel, and this is only my opinion, that handing Y the crown after defeating them is cowardly. I feel that if you swear an oath with all of the information on the work involved in being King/Queen, and fight people who think they can do the job, and defeat them, that it is now your responsibility to fulfill the duties you signed up for. By defeating everyone else and handing the crown to the other guy, what you are saying is, "I just wanted to show how awesome I am, I didn't really want the job and this sucker can have it now, aren't I just so awesome?"
This is not honorable but to me does say that X would have made a terrible King. Personally I don't think being able to kick other people's butts is a good measure for the top spot in administration, although I suppose it is a good way to shut down people wanting to argue with you. Disagreeing courtier 1 "But Sire, are you sure ordering every fighter to fight is purple paisley tights is a good idea?" King "Do you want me to prove how right I am with my sword again?" No longer disagreeing courtier, "No no Sire, of course you are right!"
Seriously, the King/Queen isn't a position that involves fighting, that is why you have guards, knights, and nobles with sharp pointy swords and maces and axes and etc....
Still, if X feels he would not make a good King/Queen, then don't enter, don't find a consort, don't make the oaths, and bottom line, don't fight. This is called common sense and forethought. Poor Y fought with all their might and might or might not make a better King/Queen, but are now going to have their reign known as the one handed to them for losing. You now stain *their* honor rather than simply losing or not fighting in the first place. This seems like attention seeking to me, not honor.
