All of this.T'Pol's addiction didn't make any sense. It was supposed to help her experience emotions? Did they forget she's a TOUCH TELEPATH? She was already getting that from doing neuropressure on Trip. It didn't just cheapen her, Phlox was negligent for letting her back on duty so fast.
Phlox I can handwave as they were in the middle of an emergency with one-fourth of the crew dead. They needed all the able bodied people they could get who weren't physically damaged. It happens a lot in war.
Story wise, tying her emotional journey so tightly around Trip did her not the pairing any favours. I don't say that to kick up the remnants of the decade-old hornet's nest, but it always came across to me as a lazy way to get them together, and that was crap that didn't need to be added to make that happen or plausible for the fans that already supported the couple.