Soraka and grievous wounds are in a very odd state
Soraka by herself is a good champion. Her immobility makes up for her being able to stay further away from the battle and heal everyone. But, Soraka has become an awful support pick because of grievous wounds. I don't mind ignite countering Soraka's healing for the few seconds it lasts, but for just 800 gold (Executioners Calling) an ADC can make Soraka useless for the entire laning phase and possibly the entire game.
It's extremely frustrating to know you can't play Soraka because all the enemy has to do is buy an Executioners Calling on the very first back of laning phase. Of course there is Morello's too but Morello's has a threshold for grievous wounds and isn't just a simple 800 gold. Other champions get affected by grievous wounds also, for example Vlad, Trynd, Volibear, Darius, etc etc. But the main difference from those champions and Soraka is that Soraka's entire kit is just healing. Those other champions can still do damage and be useful even if their healing is reduced. It's a negative effect on them but doesn't negate their entire champion's play style and kit.
Quicksilver sash's ability to remove ultimates like fizz ult, morde ult, zed ult, warwick ult was taken out of the game because it was a direct counter to the champions unique spell kits and made those champions ults useless once QSS was obtained.
Now I'm not saying grievous wounds should be taken out of the game because it is completely negating Soraka's playstyle, but Soraka should have some accommodation in regards to grievous wounds.
Either make Executioners Calling not have grievous wounds effect until the very last weapon upgrade, similar to Morellos. (It doesn't even build out of items that give grievous wounds, it's just a final item that has the grievous wounds effect slapped onto it.) This would allow Soraka more time in laning phase to have an impact on the game without being shut down during the first 10 minutes and this would also make the ADC's sacrifice building straight damage early game for the armor pen item that has grievous wounds. I mean sure Executioners Calling is a sacrifice that ADC's make to purchase but for 800 gold its value vs Soraka is completely worth it.
If changing the effect on Executioners Calling isn't an option, maybe change the healing aspect of Soraka. Maybe her heals ignore grievous wounds on allies with less than 50% or 40% or 25% health. This way she can actually do what she does and save allies when they are near death while not being able to heal them efficiently when they are above the threshold. Hell maybe even just make her ignore grievous wounds altogether I mean she's a champion that is solely based on healing. It would make sense that a Champion whose entire kit revolves around healing, has the unique ability to ignore grievous wounds. (Soraka healing without grievous wounds? What is this madness?)

Kappa.