Turret suggestion: shockwave bolts

Here's the idea, improve on it if you want cause it's not finished yet:

When a tower strikes an enemy champion (not minions), the bolt does 50% damage within a small radius of that champion (like rageblade size). Damage ramps up with normal tower ramp-up, though at reduced ratio.

What does this do?

Multiman pileups for tower dives are not as easy, but solo dive champs (think jax, irelia, whatever) see no change. This would make those early-game 3v1 tower rushes kinda crap.