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 
Who said anything about rules? I'm just wondering if what you're saying has any basis in, you know, reality.
You, when you got on my case for referencing discussions and things I'd seen outside this thread.
Here's a discussion about the marketing for 09, to refer to an example of what I'm talking about.
The Kurtzman era of trek's default is to be embarrassed to be a spin-off of a campy 60s sci-fi show. For me, Beyond, Prodigy, and Lower Decks are the handful of cases where they don't seem to be trying to "fix" or "solve" being attached to TOS.
Quote me, with a link, where I said something about the rules.
And I'm putting the mod hat on now, because being truthful is a rule here, so you'd better be 100% honest and accurate with what you provide.