...why in Season 4, after she enters Starfleet, T'Pol isn't made to wear a standard uniform?
When she was accepted into SF, she would have to abide by their rules and regulations and comply with wearing the uniform. I can't think of any decent arguments for her keeping the catsuits but just adding a little trimming to them, unless Archer just wants to perv over her.
The times we did see her in the uniform she pulled it off very well, acknowledging the fact that she is a curvey woman but also making her look professional.
Was there ever a reason given?
Commander Austin Harris, First Officer, Deep Space Nine (by FltCpt. Bossco)
8.01 - Darkest Before Dawn
(Chapter 8 added, 12/09/2015)