For someone so infatuated with Smashing stuff Galio doesn't do it enough
Half of Galio's VO is him being all jolly about smashing mages and punching bad guys...
And in game he just one-shots people with his Q.
Now, I really like Galio but ever since his rework Riot just seems to have no idea on how to handle his balance. They seem to want him to be some sort of durable AP bruiser but the way he goes about that currently is no different than any other mage.
What I'd personally change about him right now would be siphoning damage out of his q and putting more value on him maximizing his passive Colossal Smash.
It's thematically fitting and by making him effectively aa weave and hit his spells to put it off cooldown more often his damage would be spread out more evenly and he'd actually live up to his champion fantasy.
Then again, this is the simplest change they could do but there are probably bigger changes he could use right now.
Just my two cents on my favorite, and only, petricite colossus.