Possible Tahm Kench nerf

So I was just playing Tahm and hit 6000 health with a Titanic Hydra, which was a ton of fun for me and not so much for the enemy team, which got me thinking of the recent, largely justified calls to nerf him, and how it could be best done. What if bonus aa damage was calculated on current instead of max health? It would probably require a small boost to the base bonus damage but it would give an actual reward for attempting to kill him and force him to possibly use his shield earlier in order to keep his damage longer. Do you guys think this is the wrong direction or do you think this might have some merit?