Playing Darius on the pbe, his heal feels a little weak, increasing it a little a bad idea?

So with the new Darius rework, if you hit the enemy with his Q on the outer blade, he heals for 10% missing health. That's great and all but that heal isn't really noticeable unless you have a LOT of health missing.

Simple math, say you reach late game and have 4k health as Darius. Say you are missing 3000 health and hit somebody with your outer Q(1 target, not 3) you heal for 300 health. It feels a bit meh but I know that if he hits more than 1 target he heals for a lot more, it just feels weak against 1 target.

I was thinking and not to be too crazy, maybe his heal scales with Q rank from 10-15% and capping with his heal at 30% still. This would make his heal 450 health if he hit 1 person while missing 3000 health.

Thoughts on this or do you think he's fine as is? If you haven't played him on the pbe, late game hitting your Q on 2 or more targets isn't the most difficult thing, but it's a huge pain because they see it and just spread out immediately, making you hit 1 target or 0.