But it could never have been made. It's not because of the numerous hostages to continuity offered by Farhi's script - language-teaching machine in the Tardis, the Doctor's belief in God, Susan's statements about their home time - these would have been weeded out in the editorial process. It is not even that the Tardis crew don't really impact events (though that is a weakness of the story). It is simply that it is too sad: Alexander's three closest friends all fall victims to the conspirators, followed by Alexander himself, leaving his realm to be divided between the complicit Seleucus and the loyal Ptolemy. As one of the commentaries in this edition puts it, Barbara and Susan shed more tears in this script than Rose Tyler does in her entire career.
We also have a bonus here, a single episode story (or perhaps the last episode of an unwritten longer story), The Fragile Yellow Arc of Fragrance, in which the Tardis crew visits a planet where one of the locals literally dies of love for Barbara. It is also too sad to ever have been turned into a broadcast story, but I think that today's fanficcers would love it - it's totally in tune with the idea of takiing the show's characters to places that the show's writers never could.
So this is strongly recommended, though for slightly different reasons than I though it might be: good emotional character-driven writing, and a glimpse of how Doctor Who mght have been.