Well, I finally watched the one TNG episode I have never seen, Skin of Evil. Not bad, but not great. One thing that struck me while watching the episode is the potential friendship that could have developed between Worf and Yar had she stayed. They had a nice scene together on the Bridge.
Ironically, Denise Crosby is quoted saying that if there had been more scenes like that Worf/Yar bit, she might have stayed!