Really, I think Blalock was outstanding throughout. She underplayed beautifully, emotion just under the surface just like T'Pol. I've read that Blalock didn't like the trellium storyline, but she just hit it out of the park even so. If the show had continued, I think we would have gotten to see her Vulcan and emotional sides in constant struggle, just like Spock, and Blalock would have been up to the task of pulling that off.
I find Jolene Blalock one of Trek's most underrated actresses. She had to walk a tightrope of Vulcan and Emotional drama and pulled it off so well. One of the reasons why I enjoy Season 3 is because of Blalock's portrayal of a drug addict and how that rips away at you. It also led the way to a much more softer, yet balanced T'Pol in Season 4, especially in the Vulcan trilogy. I wish the writers/producers wouldn't have pissed her off because I would love to just hear her talk about the role after all these years.