Wales is a principality, not a kingdom. I think that has something to do with it.
My understanding is that Wales was allowed to remain an independent principality under the control of the Prince of Wales, which is why it’s not included in “King of ES&NI”).
I’m aware it has no truth value, but the Elizabethan era anecdote that was told as truth anyway and has some “truth in myth” value is that the Welsh leaders offered to accept Edward I’s souvereignty IF he would appoint a Prince of Wales and who met the following conditions:
1- The Prince must be born in Wales
2- The Prince must not speak English (implicit was that he be a native Welsh speaker, but the exact words were “does not speak English”)
3- The Prince must never have taken up arms against the Welsh at the behest of England
Edward signed the treaty (according to the story) and promptly named his newborn son, Prince Edward (later Edward II), born in Wales while his father was on campaign and who being an infant spoke no English and had never taken up arms, as the first PoW.
About the only truth in this is that Edward II was the first Prince of Wales and was born at Caernarfon Castle in Wales, the rest is much later invention. Still, it’s an interesting story that explains some of the English-Welsh relations.
There was a National Geographic article a few months ago about Prince Charles and how he’s actually the most conscientious PoW in many generations with his Welsh Revenue. He’s used it for major beautification and charitable activities.
The Hawaiian flag makes my head hurt without adding any dragons, thank you very much.
Hey, I like the Welsh flag.
They’re welcome to it. As some of us are to an independent East Anglia, thankyouverymuch 
(Actually a terrible idea in so many ways, but hey)
Really? What did he look like before he used some of his revenue on plastic surgery?
Well that was indeed money well spent and I’m sure his subjects in Wales thank him heartily for it.
Maybe they should revive all 7 of the old Saxon kingdoms, just for the hell of it. I get dibs on being king of Kent…
But East Anglia wouldn’t be a Saxon kingdom, would it? It’s the Law!
The Danelaw:)
How are the countries you mentioned represented on a flag basically comprised of a mix of red, white, and blue criss-crossing lines? Sorry, I hope that did not sound terse…no offense intended.
Tell that to St Edmund 
Union Jack - Wikipedia expains the history and development of the design
Nah, 50 little dragons instead of stars.
Would you rather he took a leek on it? 
They should have removed all but a sixth of St. Patrick’s flag from the unionjack long ago. 
Isn’t that the flag of the United Weyrs of Pern? 
No, all of it, and towed Ireland five hundred miles out to sea.