This whole discussion raised a question by me. If T'Pol is considered less emotional mature/adult in the eyes of her fellow Vulcans, why was she selected for the important task of being first officer on a Human ship? Did they saw it as opportunity to use the "more emotional" T'Pol, because she would be able to interact more with the emotional Human crew? Or did only her mother saw her that way, disappointed that her upbringing of bringing control over emotions seemed to have failed (and she would know T'Pol more privately and able to judge how much she was in control as opposite to Vulcan strangers).
In the novelization of Broken Bow as well as the original script (I don't know if it was filmed) Trip and Archer have a conversation about why T'Pol is assigned to Enterprise. Trip still thinks she's a spy at this point, but Archer somehow has reason to believe that the Vulcans are using her as a guinea pig to see if a Vulcan can handle being on starship and constantly exposed to human emotions. It's clear from their conversation that they don't believe she's aware of this motive and they end up sympathizing with her. Archer seems to recognize this is a crappy thing to do to her.
The scene was cut, but I remember liking it because Archer actually does show some compassion for her, and it seems clearer than in the rest of the script that Vulcan behavior rather than Vulcans themselves are what irritates him.
So, perhaps the fact that T'Pol was emotional for a Vulcan to begin with prompted her career choices, her isolation and perhaps even the Vulcans being willing to use her for difficult assignments such as in The Seventh and later being assigned to Enterprise.
When I get home, I'll see if I can dig out the novelization (which was pretty crappy, mind you) and find the text.
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