#this is all a direct result for him being cheated out of an in lane ultimate ability
you can not balance a damage champion around 2 damage abilities (no ultimate) ((ignoring passive))
basically it comes down to he either one shots you with his combo or he has to wait a solid 8+ seconds to do it again after crawling away from melee range going "please dont kill me in these 8 seconds, ty, ima just walk out and hope im not in a terrible position"
i said this a long time ago. ap galio can not be balanced, it will always be he one shots you, or he doesn't. pre buff galio always came close, but could never do it. new galio barely does it, but its enough.
annies scaling totals including her ultimate are 80, 85, and 65 ( 230)
galios scaling totals excluding ultimate are 70, 90, 90 (250)
basically tone down galios passive to 60%. Q to 75%, and E to 80%. so he can have a 215% combo. where a lich bane will probably do it. (id argue it should be closer to 185 or 190 to truly be fair, but then he wont be able to kill anyone again, just deal a big chunk, which might be a bit fairer forcing him to poke a little with Q before hand)
i feel like most of the damage should come from his E, forcing him in, passive is too strong right now thats for sure.
i refer you all to old AP sion, who had 180% ap damage on just Q and W where he walked around with the shield, flashed in, stunned the carry, and then popd bubble for tons of damages, and if necessary finished him off with 1 auto lich bane. but at least he had to flash to do it.