What are Galio's weaknesses?

The biggest weakness not mentioned is he falls off late. If you build tank the tank items lose their value and full ap feels weaker lategame too. Esepcially when you against a mobile pos like Vayne or Lucian you cant hit with anything.

He is too strong now, you can hardly lsoe lane.

From his design, it's clear his supposed weaknesses are suppose to be his slow windup times for nearly all his abilities, however, I would argue he is pretty strong right now due to simply being overstated.

His engage is pretty easy to dodge, he's pretty vulnerable to kiting, AD champs cut through him pretty easily. While he's pretty good at dueling, he loses to actual duelists, like Fiora.

Physical damage and he's fairly immobile. Sure, he's tanky, but he doesn't burst people down especially well in the mid-to-late game and only gets to act as a disruptor after a bit. I actually think he's the best tank in the game right now because he gets a strong enough early game to make it to mid and late, but he still gets to do his job as a damage sponge when he gets there.

I still see people go 1/12 with him.