The Balance team being Diamond+ IS the reason Galio was released in this state
Why would I say that? Easy, because Galio, especially full AP Galio, was BALANCED in higher tiers of play after the changes. The playtest and balance team consist of high rated players so the changes to Galio's AP ratios causing him to build glasscannon was more easily abused by these players.
As backed up by statistics. https://www2.pic-upload.de/img/34192891/galiodia.jpg
https://www2.pic-upload.de/img/34192897/galiogold.jpg
https://www2.pic-upload.de/img/34192900/galiobronze.jpg
Lolalytics back this up too! https://www2.pic-upload.de/img/34192907/galiololay.jpg
AP Galio wouldn't have been deemed a disaster if more people knew how to properly abuse his AP build, leaving him now in a pretty weird spot after the hotfix. https://www2.pic-upload.de/img/34192903/galiololalytics.jpg
Still, calling the balance team out for being "Silver" was unwarranted, especially seeing that AP Galio was totally balanced in higher tiers of play. I think the nerf to Q was a good choice though and it shouldn't be buffed in any ways, if he needs more power there are other areas to buff him.
Just wanted to point that out.