More fun from DnD Next
Selective Area
Magic Feat
You have trained yourself to avoid your friends why destroying your enemies
Prerequisite:6th Level
Benefit:When you cast an area spell, you may select a number of creatures in the area equal to your spell casting ability score. These creatures gain advantage on their saves for the spell.
Thoughts?
Throat Punch Games 
I am liking the feel of this feat. May be a bit complex to some or over powered in the wrong hands.