I’m going to be honest, Klingons in the TNG era always felt too goofy to me. They weren’t a proud warrior culture so much as borderline clownish space vikings who spent more time getting drunk than actually conquering anything. A redesign and change in how their culture(s) present on screen was welcome for me, and I think Discovery did a great job. I even liked the way they recontextualized the Klingon language, to make it sound more alien and more threataning than the staccato, oft-mispronounced mess that we got in the TNG era.
That said, I also think there was a missed opportunity with them. For a long time, I’ve had a head canon of the different looks of Klingons throughout all of the eras could be chalked up to these all being distinct peoples from within the Klingon Empire. It stands to reason that over a long enough time scale, an empier spanning multiple stars would start to consider people not originally from their homeworld “Klingon,” even if they might be genetically different. I always thought it would be cool if the TOS smooth forehead Klingons were actually just one species that were culturally Klingon, where the Worf-type were another, and the General Chang type was yet another. It would provide a way to smooth over the aeshetic differences with an in-universe explanation that doesn’t require any retconning except for a handful of episodes from ENT that die-hards didn’t like anyway.