I think you are overexagerating Galilea and Miko. Both have been nerfed. Galilea in the beta, and more recently both of them got a nerf. As it is you should be figuring out her strengths and weaknesses. Some characters can’t take on a Galilea 1v1. Others can destroy her without much thought. I’ve personally 1v2 a Galilea teamed with a Miko many times. All it takes is the right character, with the right helix choices, and careful strategy and skill usage. Personally, I don’t think they need to be nerfed at all anymore. Actually didn’t think they needed the most recent nerf. Both have weaknesses against certain characters and strategies. I main with Thorn, and she is very good at killing Galilea. It’s pretty dangerous before level seven, and very dangerous before 5, but after I have the right helix choices, and gear activated, I can plow through a Galilea. Area of effects, slows, speedy character to get around the shield. Kill the Miko first and quickly. Damage him till he starts to back off, then finish with ULT, then kite around the Galilea while they struggle to get in melee range. Any character that struggles with melee fighters is going to have a hard time with Galilea, but others can take them out with the right know-how. If Galilea or Miko is nerfed any more, they will end up in the graveyard of unused characters.
Also a Miko teamed with Galilea is nothing to worry about compared to a smart Miko healing a smart Montana. They can hold a defensive line so well.