Update: guy at a Portland retro game swap roasted my soldering and now my Xbox pad rebuild actually works
I was at the Portland Retro Gaming Expo swap meet last month showing off my modded Xbox controller and some old timer pointed at my stick drift fix and said it looked like a bird pecked the solder joints. I got mad, went home, redid every joint with flux and proper heat instead of just blobbing it, and the drift has been gone for 3 weeks now. So was he right to be that blunt, or did he just get lucky guessing my work was sloppy?