I asked in general discussion what the consensus was on how many boons characters could have and there was no reply. I propose each character have 1 "boon slot" that they can receive/buy boons for.

Too many boons hurts the character item limit balance. For example, there's a boon that exactly mimics one of the best heroic foot-slot items (Boots of the Fencing Master) but doesn't take up the foot slot.