To me, Miranda Jones was one of the most interesting guest characters in TOS - someone who was rejecting humanity and was totally cold to any of the human(oid) male advances - something that was really unusual to see in TOS - and was more interested in a spiritual relationship with a non-corporeal (?) alien. The entire episode is so unusual in its theme, and even visually at times - which is why it's one of my favorites. TOS did have interesting/strong guest star female characters occasionally - Miranda, Vina, Romulan Commander (although it was disappointing that she would fall for their deception so easily, a problem that D.C.Fontana had with the re-write of the episode), Edith Keeler, T'Pring, T'Pau... I always liked Uhura and thought she had a potential to be a wonderful character, but she rarely got anything to do, and was written inconsistently - there were far too many episodes where she would be given "girly" moments - screaming, saying "Captain, I'm frightened" etc.Both of Diana Muldaur's characters were good in the positive regard, though - Miranda Jones was also a capable, confident character. One can see why they decided to bring her back for TNG.