The RoE in it's current incarnation is frankly underwhelming. I feel it would be an ideal candidate to change into an Amulet.
As an Amulet, if you equip one, then that minion would be the only minion taken into account for XP rewards (like the way the current RoE works). If you added additional Amulets, then only those wearing one would count for working out division of X rewards.
So on a 4 Minion team, if two minions wore AoE, when X was rewarded only those two would get XP, exactly if the team was only two minions in size.