What if Aftershock was based on the user's % resistances?

For example, you gain 25% armor and MR when it's procced. (Just throwing a random number out there, probably not a good number).

So let's say you have a Maokai with 300 armor and 200 MR, he would temporarily have a net gain of 75 armor and 50 MR, which is fairly useful.

Then let's say you have a Lux with 50 armor and 40 MR, she'll have a net gain of 13 armor and 10 MR, which is significantly less useful, and this would go for all ranged champs who can abuse aftershock. (Lux and Lissandra basically).

The reason I'm proposing to base it on % resistances rather than something like melee/ranged is that I still want champs like Thresh to be able to take Aftershock if they want and not be forced to use Guardian.

Idk, it's just an idea. I know that only like 2 ranged champs ever abuse aftershock at a given time so it's not much of a problem, I just think it's really annoying when it does happen.