If you really want to go back, what about the "King" Harley Race? Or "King"Mabel? Or "The King of Harts" Owen Hart.
I understand how the OP points out Austin, Brock, Edge, Angle even, but the fact is, usually the winner of the KoR gets a "King" gimmick of some sorts. That's the way its always been.
Sums it up. the people that didn't take the King gimmick are in the minority.
the ones mentioned as not taking the gimmikc were during the attitude era. Guess it woulda been seen as gay if they did the whole im a king thing.
Brock/Angle did wear the crown and cape briefly though.
irregardless those guys didn't need a huge push, they were already big stars or on the verge.
Really it's just another visual title of sorts to say, hey look this guy is going places unless he screws it up, don't need the crown etc. but without it they are aren't really any different to the way they were b4.
as for Wiiliam Regal well he's different, he pretty much always played a Royal snob/gentleman type character hence the surname "Regal". Just didn't don a crown and that stupid fur robe. The exception was the "Man's Man" - Lumberjack style persona he had during the attitude era when they brought him back from being busted for drugs.. the fact he won the King Of The Ring in 2008 is irrelevant.
Sheamus i think is just a way to keep him rellevant while they don't really use him in the title scene, and the obvious direction is a return series with Triple H to determine to real King Of Kings even if they is obvious and a little lame
On a side note, Time for them to bring the KOR back as a PPV the month or 2months b4 SummerSlam. get rid of one of the others and KOR can setup as the winner gets a title shot at SummerSlam like it originally was. it would still be a themed PPV, the only time of the year we have a 1 night tournament. it's lame having tournaments of only 8 guys that are shown over 3-4weeks.