Now I may have this wrong, and with all the fanfic I read, it's not implausible, but I thought T'Pol's catsuits had a thermal element to them to keep her at comfortable and manageable temperature because Enterprise would have been set to a human's comfort level, not a Vulcan's.
Having said that, if that is true, what about Phlox......thank goodness we never saw him in a catsuit. SHUDDER!