My brother is bald and I have a full head of hair.... Must be some type of family reboot or recon going on!
Seriously I remember seeing a site which examined all the variations in Klingon ridges. There was no ridges of TOS, very high pronounced in TPM but the other TOS films were more subtle. With the TNG it was kind of between those two.
Their idea was that Klingons like Chang could have had implants to hide the effects of the virus in ENT. Bottom line it's much more interesting to see all these variations in makeup and hair style. It always bugged me that in TNG/DS9/VOY era that every Klingon, Vulcan, Romulan looked exactly alike in clothing, hair and makeup. That's not believable or interesting. Though any times variations have been tried some fans feel a mistake is made or has to be explain....
We have to explain why some Klingons have piercings and others do not? Really!