Georgia are already moderately strong. The illusion that Georgia are weak just exists in your heads. Walls are OP and they have the best walls in the game.
Though I would like an indirect buff that makes Dark Ages worse and Golden Ages stronger. Alas, that already exists as a game mode.
As for the buffs I'd like to see:
Yes, buffing the HORRIBLE leader abilities of Peter and Billiemina should be top priorities #1 and #2.
Lautaro's ability should be altered so his loyalty reduction doesn't istantly vanish OR cripple his army.
Some of the vanilla tile improvements, especially the Kurgans should be reworked.
Tomyris's LA should once again apply to religious units (why they took that away, I'll never understand)
I'd also like to see Gran Colombia and Babylon nerfed, tyvm.
While nor a buff or a nerf, I'd like to see them alter some of Korea's abilities, just to make them more fun to play.