My suggestion came from playing my frenzy barb. Projectiles are infinite and I noticed Double Throw was removed from Barbarians. Not sure if it's a possibility but my idea is basically Frenzy does the same thing for both melee weapons and throwing weapons.

"Allows you to swing or throw two weapons at once
Each successful attack temporarily increases your run and attack speed
Requires you to equip two melee or throwing weapons"

Small implementation that would make a huge difference. Otherwise, please re-add Double Throw