Just came across something interesting that may be of help. I'm going through the companion book to the Ancient Egyptian Tarot and have gotten to the Minor Arcana. In discussing the elements associated with the Minor Arcana, Barrett says that "Fire is regarded as the highest and most spiritual of the elements."
When discussing the dual application of the elements to the courts, he says, "the King of Wands is regarded as fire of fire. This means that in this card the associations of that element are at their strongest and most powerful. It suggests a person who is very active and energetic."
Understanding that what I'm about to say may not apply to Thoth-based decks, I think everyone so far agrees that from lowest to highest in the court ranks we have Page/Princess, Knight/Prince, Queen, and King.
So how one views the ranking of the elements seems to be the determining factor of whether the King or the Knight/Prince is fire or air. Is it earth (at the lowest end), air, water, fire (at the top end)? Or is it earth, fire, water, air? In the former case, we have the two sets of opposites next to each other - earth/air and water/fire. But in the latter case the only set of opposites that are next to each other is fire/water. If you look at the contrary elements as balancing each other instead of weakening each other, the first system is balanced, while the second system isn't.
I'm not saying either system is more right or wrong than the other, but just wanted to share the AHA! moment I just had about fire being associated with Kings instead of Knights/Princes.
Rodney