One thing you still didn't mention is have you taken the actual wetside off of the glass/acrylic and check to see if the impeller spins?
One thing about vortechs that differs from other pumps is that other pumps have a ceramic shaft usually, vortechs have a ceramic bearing (disc with a hole in it), now that's going to heat up in any pump simply due to friction, unfortunately it also is a place that stuff precipitates to because of the heat (its why heaters tend to have a crust on them after a while) and the result is that ceramic typically fuses to impeller. Now in a typical pump (ceramic shaft) that often isn't that much of a problem initially because the shaft itself can spin (although it does a number on the rubber spacers at each side), however with a vortech that disc has notches in it that prevent it from spinning so if it fuses to the impeller you'll often get the impeller falling off the wall, however with the new EcoSmart driver it might sense the bind and shut down (i'm not sure I don't have the new drivers), however I seem to recall older drivers did as well.
Hell if you dont want to take the impeller off stick your hand into the tank and see if you can't spin the impeller with your finger, it should spin relatively easily.