I would love to see some synergy between Fel Eruption, Fel Barrage, and Throw Glaive (Master of the Glaive / Bloodlet)... Maybe have Throw Glaive give you a buff that the next chaos damage ability you do deals 20% more damage, or something? Less useful for Chaos Strike spam, but good for a longer cooldown, heavy hitting attack. Perhaps Bloodlet could also have a chance to gain charges for Fel Barrage, as well?
It could give us a potential third spec to play with?