When she was on, Tonia had some wonderful triple jumps and a very energetic presentation for her competitive performances.
She had the misfortune of being one of many highly talented women in the figure skating "pool", and as such, she remained a rather small fish in a large pond.
I also thought that Tonia lacked the competitive toughness that is needed to win major titles. This isn't meant as a criticism, as Tonia always comes across as an incredibly nice, sweet, down-to-earth person. And I'm certainly not insinuating that Michelle, Tara, Kristi, or the other women who have won US titles were some kind of mental "terminators". However, these women were able to harnass the mental focus, the confidence, as well as the technical and artistic skills that are all needed to win. Tonia just fell sort of being able to package all of these elements in her skating.
Tonia's coach Carol Heiss once said (to paraphrase), "I sometimes
thought that Tonia was just too darned nice for her own good. A woman has to have a killer instinct to win, and Tonia never developed that."