More things I pick up during rewatches:
It's crazy how often scenes between the police department and the criminals parallel each other during episodes. For example in Episode 10 of season 2, the same time Prop Joe/Stringer join forces is the same episode the Baltimore PD and the Feds join forces. Another example is the scenes when Poot and Bodie walk up the steps to kill Wallace, and when McNulty and Cedric come to arrest Avon and Stringer. They both walk up these dark single steps, in the Poot and Bodie one, Poot hesitates to come upstairs until Bodie gives him a head nod like "come on", and in the reverse, McNulty hesitates to come downstairs until Daniels gives him the head nod to "come on".
In Season 1 when the MCU brought the Barksdale case to the Feds, and the Feds wanted to leverage Avon and Stringer and flip them to snitch on politicians because the Feds said they are the real targets, not Avon and Stringer, they were actually right lol. They are way more corrupt.
The Wire, X-Files and Law In Order all exist in the same Universe due to Detective Munch's cameo.
Ziggy didn't steal the right cars for Glekas lol, he stole him C-Class Benz not S-Class ones he asked for. Which is a huge difference price wise. And Ziggy actually kept one of the cars because that's the type of Benz he drove when he went over to see Glekas, and even told him he had one outside. If Glekas would've took Ziggy up on his offer to go outside and see the car himself, he would've known he ironically overpaid Ziggy.
Kima and Bubbles have no interactions once he gets clean
Dee and Namond are basically the same type of person under the same circumstances (Forced to be in a game they're not built for due to the reputation of their family name)