Redemption is too strong outside a team fight scenario

I had an idea the other day, with Redemption being built on almost every support I think something should be done to expand support itemization.

What if the heal from Redemption scaled off of nearby enemy champions?

This would make it less effective to back off from a team fight and heal your entire team up and instead require it to be used in the middle of a fight.

What are peoples thoughts on this?