@Statikk, Meddler: Let's talk Soraka in terms of Class/Subclass.
So, you guys put out the dev blog talking about classes/subclasses. And I want to talk specifically about Soraka. She fits best into the Enchanter Class, but she's incredibly unique in that rather than enhancing damage (nami E and Janna E), Enhanced Mobility (Karma E, Lulu Whimsy, Janna Passive), or other enhancers that are common to a "Protect the ADC comp" Soraka is unique in that she completely negates damage done.
However, I want to talk specifically about adding in another potential subclass to the Enchanter and Disruptor family. I'm talking about adding Healers or Medics. The big problem with Soraka, is that she's unique. She's League's Premier healer. This leads to some interesting issues in regards to game health when Soraka is strong.
In the past, SOraka's healing was opressive because there was little to do to stop her. So you generally nerfed her to keep her weak so that she wouldn't crowd out competition because she was "Boring". You hoped to fix this with her rework. It helped some, but after the pre-season changes to GW, Soraka went overboard, and nothing you've done has really stopped her.
Anyways, I detract somewhat. I've been a Soraka main for years, and have well over 100k champ mastery points with her, 90k of it earned before the pre-season changes to GW. What I'd like to see happen, is Soraka no longer be the exclusive healer of league. Keep her the most potent healer, but rework Sona to be a more "Battle healer". Emphasize her Shield+Heal combo. Make it so that Sona has a unique spot again. RIght now Sona is muddled and feels bad to play because her "Enchanting" is so diluted. Her poke is strong, her ult is gamechanging, and her W and E feel underwealming, despite holding vast amounts of power in their bubble power.
When you finally get around to reworking Sona, Make Sona a more offensive oriented version of Soraka. Make them fill a niche of "We're leagues healers." but have each one satisfy a different gameplay. Soraka is a mroe reactionary and defensive chioce, while Sona would be a more offensive proactive choice.
TL;DR Soraka is a unique enchanter, but Riot could help better balance Soraka by having her have a companion that is an opposite in purpose. Sona would make a good canidate for a proactive, offensive dedicated healer, while Soraka remains the reactive defensive healer queen.