I actually think support Galio is legitimately good
Maybe even sleeper OP tbh
I've never been a fan of solo lane galio. While he has really strong wave clear and is relatively safe in lane, he's just too inconsistent of a champion id want to depend on, especially as a damage dealer. More to the point, if you're taking him mid for just wave clear or his utility, there's champions who offer much more in both scenarios.
However, bot lane, a lot of this changes. For starters, he has extremely long range poke that can pass through minions. The one draw back is potentially taking some CS so you gotta be careful when to poke and when not to. Or steal your ADCs CS, fuck em. His utility is pretty damn decent in the form of his W/E and his Q/R are good peeling tools. You can always go mikheals on him too because of how good chalice is on him. He outpokes several supports as well. His biggest draw backs are mana and consistency still, but he has high reward potential and it's less punishing to him as a support. A 5 man support Galio ult is still going to be game changing.
However, I believe I've got a good setup you could run on him. Feel free to try it out. If for nothing else, trust me, it's fun as fuck
Masteries: 0/21/9 make sure to take points in mana regen, etc
Runes: 3 Flat Armor Quints, Mana Regen Yellows, Scaling MR blues (you could run flat but I love scaling) and magic pen reds
You can start any support item but I prefer
for mana regen and a little AP though.
So there it is, abuse this Freelo while you can.