See, the trouble for me really begins because it does lack consistency with the Klingons in TOS. Oh sure, the excuse could be made that the Klingons in "Errand of Mercy" had their own interpretation of ethics and honor to which they were subscribers, or that as military officers fighting against the Federation in a state of near war, they put aside those rules of conduct (or 'interpreted' them very loosely). But on the other hand, there's little indication that TOS Klingons care for honor at all.
And what of "The Trouble With Tribbles?" Poisoning Federation food supplies to take over a planet doesn't sound honorable at all, nor does having an intelligence operative sneak behind enemy lines to do the deed seem like something a warrior race would be capable of. Rather, it sounds like something Cardassians would do.
When Kor, Koloth and Kang reappeared in Deep Space Nine, I barely recognized them. Not because of the prosthetics or costumes, but because the Klingons
themselves had been so radically changed in the interim that none of the three really acted like Kor, Koloth and Kang anymore. The characters
were very different on a basic fundamental level, despite obviously being the same actors.
The reason I mention it is because of the three, Koloth is probably the one whom I least
recognized as being anything like he was in "The Trouble With Tribbles". And I don't think it was just because Bill Campbell was playing a much older Koloth. It was because he was playing a Koloth who had to somehow act in a way that felt like what the Klingons had become. And it wasn't an easy fit for him.