Healing should not be balanced around every AD champion and their mother giving Grievous wounds.
To those who don't know, on PBE they added an item that cost 800 gold, grants 15 AD, and makes all physical damage apply Grievous wounds for 3 seconds - and it combines with Last whisper for an item (that makes it last 5 seconds) basically every ADC and Assassin will buy, along with many bruisers and juggernauts.
This means that healing overall needs to be 66% stronger to be relevant, a philosophy Riot is fully endorsing for lifesteal. You literally need to be trying to end up with less than 40% lifesteal late game on ADC's. (15% from masteries on crits [which ADC's get 100% of now], 12% on Mercurial, a new top tier AD item that grants 12% for ALL physical damage, and another 5% on red pot)
This in turn means jungle and lanning minions are an even better place to top off on health, and screws anyone who isn't AD that needs to fight someone with Vamp, Crazy Regen, or a Soraka.
Rock/Paper/Scissors implies there's a meaningful trade off for each one; Giving everyone a free Rock then buffing Scissors to the point it can take on Rock makes the game suck for everyone.
And I doubt that it's a fun game to play with healing in the first place.