It is not the lack of prot blue, nor the fact that this scales half as well with number of attackers that makes it so much worse than Piledriver
While this will mostly be relevant in casual play, it's worth pointing out that if you have a Naban, Dean of Iteration on the battlefield, every Wizard that enters the battlefield will trigger Warstorm Surge, Fathom Mage, Angelic Chorus, and Purphoros, God of the Forge (among others) an additional time, which opens up an entirely different layer of deck-building potential that was missing with Panharmonicon, which only triggered abilities on artifacts and creatures
Of the big three TCGs - Magic , Yu-Gi-Oh
I dread to think how much my family has spent on them over the years
Leading the Masters of Evil deck is either Davros, Dalek Creator or Missy, letting you pick one or the other to lead, but not coming with a companion like the other Doctor Who decks