Bring back DFG, except for what it was meant for; tank busting.
Problem with good ol' DFG was that it gave a blanket 20% increase to magic damage and dealt 10% of the targets max HP as magic damage.
So what if the % damage increase was proportionate to the amount of magic resist the target has? As in, instead of making it do that let's just make it deal 100% of your magic damage as true damage in an aoe and heal you for the same amount while providing a shield and movement speed based off the amount of damage dealt because I just realized how cancer this idea would be so why the fuck not ¯_(ツ)_/¯?
with

they shouldnt 1 shot
. ADCs or Sustained damage is what kills tanks. burst is what kills sustained damage, tanks are what kills burst. its a game of rock paper scissors rocks being tanks , paper being sustain damage and scissors being assassins, we know paper beats rocks , rocks beats scissors and scissors beats paper. or
beats
beats