Alarak's Lightning Surge would fit right into League in some shape or form

Alarak's all about manipulating enemies and punishing mistakes, and his Lightning Surge does this marvelously.

#Lightning Surge Deal X damage to an enemy and an additional 100% damage to enemies between Alarak and the target.

It only does modest damage if you direct-target an enemy with it, but if you set up positioning so that your enemy is between you and and the target, they take double damage (which is increased again due to Alarak's trait, but that's besides the point). This would be such interesting gameplay to add to League by letting you punish enemy positioning in creative ways.

Riot, please look into adding this one. It'd be so much fun.