When Old canon is ignored or removed by the current show, we tend to call it a retcon man.
Not really, so they are bald, big deal. Also, having hair would not stop the pits from working, but would make them less effective. Those pits by the way, are not just on the head, but chest and back to it seems. Really, having pits kind fit klingons, they are predators and IIRC they had actors kinda move their heads around and sniff the air and such in the past, so it really fits.
I really think they went hairless because they more based it off early TMP klingon redesign ideas.
There are many ways they could do them without making them look human, which is IMO just lazy. If they are gonna keep it, they still need to look alien, something like TNG version of klingons could work or as you say fewer or less defined ridges. I would not utterly hate it if they made them look cool and not just human.
I really enjoyed the skin tone range myself, I mean humans sometimes do get near purple. There is this black model with skin so dark it looks painted and their are people with medical conditions that turn skin blue or purple. And really, it just made them seem more alien to have skin tones that were not a 1:1 to the human range