galio main here....
galio doesn't need changing at all, hes perfectly fine as is, everyone just plays him wrong.
his base damages are ginormous, build penetration and you chunk the whole enemy team, galio isn't meant to be a damage dealing laner, hes a team fighter and thats where he excels. (but he can be a killer pending build, ie abyssal sorc boots and ludens will crush enemy mid laners)
->
mana costs gone.
full build
flex fill item, can be any one of these
you can replace these items as needed or what you think would work in a given situation, but ATM galios never been better with item choices.
before it was grail 100% of the time, but catalyst changes = options for galio.
** you E + Flash ult, your team follows up, you win the game**
it is that simple and everyone always tries to be a hero or think "i didn't 100-0 them... galios worthless" but its just the opposite.
if anything galio is too strong right now
but since hes so rarely picked... your team or the enemy team has no clue how to play with or against him, getting a good team with a galio is just freelo. you group up with galio, go some place together, and the objective is yours
it is true that galio lacks in the carry department, he does lack a 4th damaging ability after all, but think of the AoE ult potential...