|This is Kor--pretty much my favorite Klingon|
|Incidentally, this Klingon is played by my BFF, Mark Lenard|
No matter what the hairstyle though, Klingons were the most conspicuous baddies in The Original Series but from the time Mark Lenard put a giant turtle on his head that was the universal Klingon look. Turtle head = Klingon.
For literally decades, it was something that the Star Trek franchise and fandom glossed over. We all knew the reason behind the change was budgetary as well as technology. The makeup became better and Star Trek got a little more money and, consequently, Klingons would forever look more menacing and less like some regular guys with bubble wrap belts slung over their shoulders.
And then Trials and Tribble-ations happened. The DS9 crew went back in time to the events in Trouble With Tribbles and Worf was asked about the completely flat foreheads of his TOS-era brethren. His answer, "A viral mutation... We do not discuss it with outsiders."
So, then came Enterprise. They said, "You know, we're about to get cancelled and we love tying together all kinds of stuff from the Treks that came before/later. Let's explain this whole Klingon Turtle Head thing."
And they do. It's yet another mini-arc (only two episodes) all about how the Klingons went from having turtle heads to not having turtle heads to getting their turtle heads back. Some people like the Enterprise explanation, some people hate it. I love it. I love Phlox' involvement in it. I love the way all these events play out and the Klingon connection to (what's probably Star Trek's best villain) Khan. I was always content with just sort of imagination retconning ridges onto the TOS-era Klingons. I never needed an additional explanation. However, now that I have one, I love it. And I'm glad I got to see my Enterprise friends do the explaining.