Some people are talking about TNG Cardassians looking different from DS9 Cardassians. I remember the different uniforms from "The Wounded," but aside from that and Macet's facial hair, I've never noticed any major differences. What are you folks referring to?
Those first Cardassians have a much more beige complexion than grey (though there's a slight hint of it in there). Their hair tends more towards brown than black. The eye-ridging patterns are rougher, macroscales less defined (that latter being a word I use to describe it in my writing), the neck ridges don't flare out as much as they do on later Cardassians like Dukat and Garak, and the ear ridges tend not to flow as smoothly down into the jaw (though I've seen this feature vary in later Cardassians).
It MIGHT even be possible that this is the only ethnic group capable of growing facial hair.
I'd say that's about a complete list.
Unlike some of the other changes in alien races we've seen, I think this one can easily be put down to an ethnic-group disparity no more unreasonable than anything that can be seen with humanity. In Macet's case, of course, this would mean that he very much takes his complexion and ridging patterns from his father's side of the family, whereas build, voice, and basic shape of the face comes from the Dukat side (presumably his mother's family, since as we've seen with the Ghemors, Cardassians are born with their father's surname).