Most of the storylines were pretty well-written (imo), it touched upon socioeconomic topics and larger issues in ways that were very intelligent but never felt overbearing, or conceited or smug while doing it...the characterizations in the show were all very true-to-life, in that the main characters were mostly complex people, with good characters committing bad acts, or bad characters doing something good once in a while, so it's morally complex and feels more realistic in that respect
The character of Omar was really well done I thought, he's probably the most famous character of the show...the world of The Wire, at least the bits revolving around the drug trade in inner city Baltimore, was divided in two, between law enforcement and the drug trafficking organizations. But Omar kind of represented his own, third way, where he preyed upon the drug dealers and lived in a bunch of condemned buildings with a bunch of hunky dudes he'd bring through lol. He was the most liberated figure in the show I think, a great outlaw character. His fate, which I won't spoil in case you ever watch it, was also very appropriate. Michael K. Williams was fantastic in that role
The way the show covered sexuality was very well done too, I thought, as there were gay and lesbian characters in the show, and that was part of who their characters were as people but never presented in any kind of "virtue signalling" kind of way
Season 3 is my favorite from the show, and it's also the one that probably best encapsulates the show's philosophy regarding the drug war etc. It's a classic, the "Hamsterdam" storyline. (Hamsterdam in the show was an open air drug market in Baltimore which was able to operate, and eventually become highly developed from an HR standpoint, due to an agreement with law enforcement). It was art transmitting a revolutionary idea in a very plausible and realistic, grounded way (but still ultimately worthy of endorsement) to a wider audience...I love that season
I could say even more but I won't lol. As you can probably tell I really liked that show, it's without a doubt one of the best pieces of film or TV done about drugs IMO