I think she would fit very well and would be another chance to explore the "divine" theme of a more badass way. She was a god [like, one punch man level god] before becoming what she is right now and would be cool to have one exclusive skin full of effects fully representing her badass feeling as a god.
"A healer gifted with the magic of the stars, Soraka holds all living creatures close to her heart. She was once a celestial being, but she sacrificed her immortality and entered the world of mortals. So long as evil threatens life in Valoran, Soraka will not allow herself peace." - Soraka's lore.
She's a celestial being, which is often referred to as an angel. She was never a God.
And why should this skin be gem exclusive? Honestly I don't want more gem exclusive skins,because it is up to your luck if you get the gems or not.
Don't get too excited. All the Hextech Exclusive skins thus far have been around the 1350IP range. On top of that, your idea for a skin for her is a tad unappealing (not to mention the "divine" theme has been explored with Celestine Soraka)
