This is pretty much intended in a facetious manner. Not so much a "Haha!! I'm so funny!" sort of way. But just understand that I don't think the producers of Discovery owe an explanation for the redesigned Klingons. It's a make-up change, clear and simple - it was never intended to be anything more than that. I totally acknowledge and accept that. And I actually kind of like the redesign (although I like Into Darkness' Klingons a little more). What I'm trying to say is that I'm not a "hater". I enjoyed Discovery for the most part. But... I still can't help it... I still find myself in my spare time, and even in my not-so spare time at work, trying to reconcile Star Trek's many inconsistencies. And this Klingon thing has taken top priority lately.
So, here we go...
In the decades that followed the travesty that was the Augment virus, work continued to reverse this "mutation". At some point in the 2180-2190's, they felt they actually found a way to do it. However, instead of reversing the Augment virus to the original Klingon appearance, it actually brought them closer in appearance to their Klingon mitochondrial ancestors (it would be like if humans were mutated to look close to something like homo erectus). Like the Augment virus, this 'cure' would be hereditary.
Many Klingons chose to take this 'cure' as it was better, in their eyes, to look like ancient Klingons rather than 'weak' humans. There were, of course, a portion of Augmented Klingons who chose to keep their human appearance for whatever reason (as we see later in TOS). And lingering out there somewhere were Klingons that somehow remained unaffected by the Augment virus. There were even some "in-between" Klingons akin to the ones in Into Darkness (yes, I know, different timeline - but again, I liked that design).
Why did we only see the augmented-augment Klingons in Discovery, and none of the other ones? Sorry, my brain cells haven't' worked that one out yet.
Again, I'm really just posting this in a facetious, just-for-fun manner. I don't NEED an explanation for the change of appearance - I totally get it. I enjoyed Discovery and I liked the Klingon redesign. But, if CBS came to me and said, "Ralphis [not my real name], what can we do to fix this?!" What I just posted is what I would pitch.

So, here we go...
In the decades that followed the travesty that was the Augment virus, work continued to reverse this "mutation". At some point in the 2180-2190's, they felt they actually found a way to do it. However, instead of reversing the Augment virus to the original Klingon appearance, it actually brought them closer in appearance to their Klingon mitochondrial ancestors (it would be like if humans were mutated to look close to something like homo erectus). Like the Augment virus, this 'cure' would be hereditary.
Many Klingons chose to take this 'cure' as it was better, in their eyes, to look like ancient Klingons rather than 'weak' humans. There were, of course, a portion of Augmented Klingons who chose to keep their human appearance for whatever reason (as we see later in TOS). And lingering out there somewhere were Klingons that somehow remained unaffected by the Augment virus. There were even some "in-between" Klingons akin to the ones in Into Darkness (yes, I know, different timeline - but again, I liked that design).
Why did we only see the augmented-augment Klingons in Discovery, and none of the other ones? Sorry, my brain cells haven't' worked that one out yet.
Although I do think Ash Tyler could serve as a detente here. Do a little retroactive continuity and say that Voq's transformation to Ash was partly in due part to a controlled strain of the Augment virus, with surgery to finish the job. He could lead a revolt of Augmented Klingons. I'm actually being somewhat serious here...
Again, I'm really just posting this in a facetious, just-for-fun manner. I don't NEED an explanation for the change of appearance - I totally get it. I enjoyed Discovery and I liked the Klingon redesign. But, if CBS came to me and said, "Ralphis [not my real name], what can we do to fix this?!" What I just posted is what I would pitch.
