In Discovery, instead of honorable warriors, the klingons are a bunch of sneaky backstabbing and coward warriors. They also don't look like klingons at all, both in appearance and architecture, the speak like their mouth is full of potatoes and for some reasons they make ships out of coffins.

I'm not against change, what I don't like is calling another thing with its name just because you get to be part of a franchise. The only thing they have in common with klingons of other series is the language and that they want to kill. All the modifications they made, just for the sake of it, makes it look like they wanted to use the standard scifi appearal of standard bad aliens and just put the name "klingons" on it. No surprise they reverted this change and discarded all of this in season two.

Btw "the klingons started growing their hair again" might be the single most stupid line I've ever heard in a Trek show, especially considering the reason why it was said.