This list could double as the list of airports I avoid. Although I frequently connect in ATL and ORD out of necessity, I try to never connect in NYC airspace. It’s just too risky.
Even if the flight is technically “on time” it may still be late. One time I was flying out of JFK on Delta. The flight was already 45 minutes late for boarding. Then when we finally pushed back the pilot announced we were #45 in line for take-off! I was glad I was on a direct flight because there is no way I could have made most connections after that much of a delay.
United does seem to like hubs prone to delays with SFO, ORD, and IAD all making the list, but at least UA is smart enough to avoid NYC airspace.