How about, instead of trashing Ornn's shield and then giving him more damage
..You change his survival spell to one that's a little more nuanced than press a button for shielding?
An idea I had for it would be damage reduction based on enemies hit with his W. Like, enemies inside the flame cone will do X% less damage to Ornn.
What this does is give him more manageable trading patterns in lane (sidestep his fire or you'll do less damage and he does more) without making it a brain-dead skill like it is currently, and ALSO retaining his ability to survive in teamfights if he's using his W optimally.
I'd personally consider this a much better alternative to "remove his shield and then put his damage on steroids," considering that Ornn is designed to be a tank and his players want him to be a tank, the sudden hard-shift into a bruiser playstyle that these changes enforce is not desirable.