It seems that a lack of willpower would start a vicious cycle. Failing once might give the sovereign more trepidation the second time around, making it easier to fail. And so on. The reputation of the king would suffer publicly. I doubt such a ruler would last long on the throne with the strong-willed and power hungry about.
Of course, the reverse might also be true. A strong king, able to intimidate all law breakers would be perceived as unbreakable of spirit.
I tried to graze the other subs to see how they connected but didn't hit on a key. Is there something the owner does to activate these different powers? Quests or judgements he has to do for them to light up? I also didn't know what other items were meant "the others" as far as knowing when they were betrayed and losing powers. Seems that would be a good spot to itemize the items that were connected...or explain how the king links items with the ring if that is how it works.
This seems like it should be an epic item, a kingly artifact to be spoken of in whispers in future generations. I like it's potential, a seemingly innocent item, that with a band of willing warriors and a touch of fealty becomes a powerful warship, or an airship to command the skies.