This is Hershey's 20th year as Washington's affiliate. In that time, the Bears have missed the playoffs twice, had one losing season, and won five Calder Cups. Agree with Appleyard that having a competent farm system is crucial in developing your developing beyond your core. None of Washington's top talent besides Carlson or Holtby (unless you count McMichael and Protas) spent significant time here but they've supplied plenty of their complementary pieces and depth over the past two decades.
Meanwhile the Phantoms have made the playoffs six times in the last 20 years and, save for the 2018 Conference Finals run, have been largely mediocre at best since leaving Philadelphia in 2009.
I know they get poo-pooed here but having a good veteran core is important in the AHL too. Unfortunately the Flyers haven't targeted the best ones in recent years.