The current rule means that any unidling Wizard loses half their hand, and if they’re unlucky enough to be holding a duplicate card they lose their entire hand - because their hand would be illegal (“No more than one Wizard may have a given card in their hand at a time”) and would be set to the default, blank value by the unidling rule. If they’re holding a card that has been repealed or Prohibited, their hand is also blanked for being illegal.

Removing all cards from unidling Wizards would be simpler, and would remove some scope for fiddly tactical idling (including the counter-play of trying to draw and hold, or repeal, a card after someone else idled with it).