"Improvement" is highly subjective. In my opinion, the Klingons never needed a redesign and the TNG ones are among the most aggravating designs, and storylines, ever to infect Trek. They are not enjoyable or interesting and the constant insistence that every Trek must have Klingons it is is aggravating, at best, with DSC being no exception. DSC is at least one of the few times that I have actually been engaged with the Klingons as a species.
Could you explain what you mean here?
To my own eyes, TOS Klingons are boring. Don't get me wrong - I think Kor and Kang were good antagonists, well-acted, etc. But the Klingon Empire in TOS was never anything more than "the bad guys" who opposed the Federation and were sneaky. Aside from finding out about Kahless, there was absolutely nothing about Klingon culture, language, art, music - anything which made them seem like a living, breathing race. That only really started with TNG, and continued with DS9.