That may be true, but while some people are asking that question it doesn't mean the writers have to answer it.
Writers pitch the story they most want to tell. If their pitch is successful, they get to tell it. If the pitch fails, no matter how original it might have been, it doesn't happen. From the very beginning of the announcement of IDW's comic, we were told that most of the stories would be remakes of, or salutes to, TOS episodes. There have been a few original tales.
This one has plenty
of new stuff. But mention Kor, and the reader instantly brings in a mental comparison to Kor of the other timeline. It's also a character known to DS9 fans. Make the Klingon a random new Klingon and we have none of that.
Imagine a DS9 Mirror Universe where they never run into any duplicates of the main or guest characters? What would be the point?
Or better yet, find the right balance between fan service stuff and telling original stories.
So you are saying the balance is wrong in this issue? Do you want us to make you a list of new and old namedrops?
Reuse a known planet and it's "Fan Service" to some readers. Create a new world and its "Planet of the Week" to others. Ban all namedrops and it's seen as Bad Robot and IDW having no respect for the parent material. Sounds like Kobayashi Maru to me.
I don't mind some references but at the same time I want some freshness too. What's the point of creating a whole new alternate reality if you can't explore it beyond remixing events and characters from the prime universe?
Khitomer. Kor. Versus plenty of brand new stuff.
Plenty in this easy was fresh to me.
The b/w alternate cover is interesting, too. Essentially the same Klingon, but with rounded ears instead of points and a different style of crest piercing.
As much as people complain about the look of JJ's Klingons, this issue seemingly flew off the shelves! I'm not sure if my comic shop has cut down on stock from this issue (I can find out). My copy was in my standing order bag, as usual, and a lone b/w alternate cover was the very last copy left on the shelf - after only a day.