I am the kind of person who enjoys “big weird” scifi like Stanisław Lem. Stories about trying to relate to and find common ground with something so alien that the prospect of even understanding is basically hopeless. Star Trek usually doesn’t do stories that, which makes sense as it often uses alien races as allegories or stand-ins for real-world human relations.
That said- I thought those early Klingons were super weird and scary because they were just so alien. It really made sense thinking about how it took a century before they could get to the events of Star Trek VI, and it made the Khittomer accords feel like so much more of an accomplishment. Like- you made a treaty with WHAT?
And just aesthetically their ships and armor looked like something out of HP Lovecraft or HR Geiger:
This is not to say I dislike how Klingons were portrayed previously, kinda like Mongols in TOS or Vikings in DS9, just that they never felt scary to me. They never felt like warriors. I was never afraid for the gallant crew of the Enterprise D (a science and exploration vessel) going into battle against Klingons. But I really enjoyed the alien-ness Disco tried to go with. Anyone else with me?
EDIT: PEOPLE I SAID WHO’S WITH ME NOT WHO ISN’T CM’ON 
Perhaps it implied that.
But it only ever implied that, and meanwhile we had other evidence that implied a separate conclusion, in the form of Kor, Kang, and Koloth.
Which is more likely-- that every Klingon Kirk encountered during his five-year mission was a survivor of the augment virus (edit: Including Kahless, who lived and died centuries before Archer!) and no Klingon encountered outside of that time period was; or that the Klingons ruthlessly quarantined or even executed carriers of the augment virus and wiped it out before it got too far, and TOS’s visuals aren’t literal?