No, no and no. I disagree firmly.
Galio's problem was not his design, but the subsequent neverending degenerate balance direction of countless changes.
We're talking about a kit designed for a tank, forced (repeatedly! patch after patch) to be some kind of... Mage assassin?
To be honest this is the "Ornn issue" (but on steroids), aka Riot being somewhat unable to concieve the simple fact that A TANK MIGHT NOT NEED MORE DAMAGE TO WORK AS A TANK. Ornn released underpowered, so they buffed his brittle passive to questionable %hp amounts of damage. He ended up winning every trade in the toplane, so he was gutted and then lost his shield.
The problem with galio? They couldn't, and can't, decide once and for all a design direction with him. What is galio is supposed to do, what he's supposed to build? Is he a damage dealer? If yes, is he an AP bruiser, a poke mage, or is he intended to have a 100-0 lockdown burst combo? Or is he a tank? Then, how much is important his anti-AP identity? Where he's supposed to go? In the toplane or in the midlane? Because having him being super effective vs AP mages AND AD bruisers sounds kind of broken.
Now, I dream of a day where galio is the guy you pick to suppress an heavy-AP comp, or to deny lane kill pressure vs some pesky AP bummer, like LB in mid or kennen in the top. His Q his meant to help him competing in waveclear with mages, for he is a direct counter to them. I would remove his ap scalings altogether, and give him his old MR ratios.