Keep the vit. Discipline to +12. 45% increase to your skills is better. Your damage range is almost maxed. You can get other bonuses on other slots. Only quiver, chest and weapon can give you max discipline. Hard to ever make it up except for a weapon upgrade. It would be like winning the lottery twice. Sure it can happen. Now you can focus getting an upgrade somewhere else.
I would take the 24% area damage myself. Drop area damage off your quiver and get the attack speed there. Quivers only roll to 20% area damage. As most people have found out, a really well rolled quiver is hard to come by. I've salvaged so man ancient DLMs because it was missing Max Discipline, crit chance, MS damage, or the orange threshold was low.
So this advice will only apply if you have a similar situation with your DLM. Of course now that you weapon is good, you can focus on cubing yellow quivers to ancient.