The buff Turrets actually need
Conditions: -Your champion is within turret range -The number of visible enemy champions in 1000 range of the turret in greater than the number of allied champions + 1
Effect: -Your champion gains +20 Armor/MR
This buff will have no effect on the standard laning phase. It would simply give players a little bit of power when on the receiving side of a gangbang/camp/premade abuse.
Edit: Some possible balancing factors: -Bonus resistances for ranged champs lowered to 10/15 -The buff goes away at 15-20 minutes