I've been over this ground enough before. I know B.S. when I smell it and nothing has changed. ENT is its own thing and no one is beholden to it including its stupid contrivances.
Fits in perfectly well with ST09, though, and it's mindlessness.
And "future generations" can ignore this just as I do the way makers of a lot of current Trek ignored TOS.
While you're entitled to your own opinion about ENTERPRISE (an opinion which I happen to share, lest you think I'm ganging up on you or some such nonsense), no amount of bitching, complaining, and telling "future generations" that they need to follow your personal line of thinking will make the series non-canon. Paramount/CBS produced and sold the show, and many talented Trek production personnel worked on the show and cared about it regardless of what the idiot suits at UPN wanted, and worked very hard to provide a highly-budgeted, quality-produced show every week for free. While I have little love for it, it's not my place or yours to say it should be ignored as if that's some kind of fact that CBS has decreed. And anyway, this rant has nothing to do with the OP anyway.
So, as far as what the OP asked, I'm almost positive that the change from swarthy cardboard villain to honorable warrior came in TNG, not Star Trek III, where Ron Moore was asked to provide a better background for the Klingons, and read a copy of the aforementioned The Final Reflection, which is what he based the TNG Klingons. While STIII featured the prosthetic and leather-bound Klingons (not counting TMP, which had the new style but zero background), they still acted no different than your typical TOS Klingon in the honor department. In fact they were even more thuggish than TOS.