Simple question, if you're planning on a four-player game, would you go with 4 mono-sphere decks?
obviously the advantages are in simplicity. Everyone can use any of their heroes to pay for any of the cards in their deck, and each of the four spheres gets some kind of coverage.
Or else would you divide it up? even in a four-player game, do you need multiple players carrying spirit cards for threat reduction or Unexpected Courage. Are there simply too few tactics cards to be worth rrunning a whole deck, and you'd rather just have a few tactics attachments and allies as minor elements in several decks?
do you think the answer to this question will change as the number of heroes available and the card pool grows?