A completely different situation. Deliberately keeping a design aesthetic unchanged over 225+ years of canon vs. recasting a character.I'd rather use a backstory which fits what we see... than play mental gymnastics and pretend we actually saw something different.
I await your explanation for why Saavik felt the need to get extensive cosmetic surgery and vocal-cord reconstruction after Spock's funeral.
Which explains the ENT Bird of Prey and everything else I pointed out pefec-- oh, wait.If we'd seen the K'tinga more than once in the 22nd century, then it would be justified to try to account for it. But if something is done only once and never again -- like "James R. Kirk" or just about everything "The Host" established about the Trill -- then it's probable that the creators themselves changed their minds and no longer wanted it to be part of the universe. In which case it's perfectly appropriate to treat it as a mistake and relegate it to the apocrypha pile.
I get that you wish Klingon technology showed a clear evolution, but it doesn't. What's wrong with citing a Ishmael's backstory which actually fits what's seen?