Wow. I'm out of time to discuss this this morning, but MAN there's a lot here I disagree with.
You're dead wrong about the Diana Rockwell thing. It absolutely is not negated by what I've done and I think it's a bit weird you keep insisting that it is. We haven't even seen that story yet, and it's only been hinted at so far. "completely guts that whole story"? Really? That seems a trifle melodramatic, considering that it's not even remotely true.
"However, in the end, it easily pares down to "she wears those colors to honor an American who died for an amazon," which takes precisely one sentence to explain."
I maintain that that explains precisely nothing. "Crest of the House of El" is clean, smart, and easy to understand. What you've said here merely brings up a dozen more questions. If you know they answers to those questions, wonderful. If you don't, you've just complicated the origin needlessly and explained absolutely zilch. What American? What Amazon? How did she die? I'll also add that there is nothing, not a blessed thing, added emotionally in that sentence, so it's hard to justify for dramatic reasons, as well.
"Crest of the House of El" doesn't need footnotes and a flashback. It is good juice. "she wears those colors to honor an American who died for an amazon," is a sentence, I'll give you that. But it's not MUCH of a sentence, and it's even less of an explanation.
We can disagree in the end, but certainly, that story has been problematic for a long time and even some of the writers you mention aren't nuts about it, if I remember correctly.
I think this, by the way, "f you'll notice, most writers avoid everything that came before them entirely, regardless of how gainly it might be" is just silly. Name a DC writer, particularly a WW writer, who avoids EVERYTHING that came before, entirely. Come on, Blue.