Original Frasier is still one of the all time amazing shows. And that is almost entirely because of the “supporting cast” of David Hyde Pearce, John Mahoney, Jane Leeves, and Peri Gilpin. It is 100% still worth watching and it is even clear what episodes/seasons they were working around Grammer being coked out of his mind or otherwise problematic.
Its not quite Person of Interest’s (paraphrasing only because I can’t look up the specific wording right now) “he is like a dog that pissed everywhere and wouldn’t stop talking about hitler” mess, but Grammer also generally seems more like a dumbass Bush-era Republican as opposed to a full alt-right lunatic. He is a piece of shit who has condoned a LOT of hate, but is also “a product of his time” as it were.
As for new Frasier? I am a lot less interested in watching that. Mostly because, as so many of us point out, “They did a Frasier spinoff starring the worst character”*
But OG Frasier? The show increasingly became focused around Niles (which makes sense since Niles was a lot closer to what Cheers-era Frasier actually was) and David Hyde Pearce put on multiple master classes as he and the writers somehow managed to perfectly capture “the adult millennial” years before we even existed. And so many of the interactions with Martin (Mahoney) hit so much harder as you have lived a lot longer and had to acknowledge the failings of others. Daphne and Roz were often stuck in comic relief mode, but Leeves and Gilpin still kick ass when they are given a chance to shine. And, piece of shit that he is, Grammer can pull off an epic monologue to close out an emotional arc and leave you on the verge of tears, right before you burst into laughter at the punchline.
*: Also, it very much bothers me that Freddy became Martin. Maybe they go into it more, but his childhood very much established him as the offspring of Frasier and Lilith. And while it makes sense that he would rebel against his overbearing parents to be like his fun and “man of the people” Grandfather, it is completely unearned. Maybe the back half of the season does that but… I still think that having one of Niles’s children (maybe a daughter) as the Martin role would be a lot more fitting. Niles dealing with a Firefighter child is comedic gold and Niles and Daphne are much more likely to “let their kids be who they are”. And it would play on The Moon Genes fears of the last few episodes.