May have missed it, but, wasn't aware that there was a 300 knot restriction at Wizard.

Doesn't really seem that different than the arrivals into LAX, SFO, ORD (hard to believe how many waypoints the Watsn1 has), MSP, NY area.

I'm sure the workload is much higher than going into a smaller airport, but, shouldn't be that much of a surprise.

Even with the FMS, still just flying the airplane.
The ASRS reports mostly come down to failing to monitor,
PF input the wrong data or deleted a waypoint and the PM didn't crosscheck it