The big thing that's bothering me about supports:
How easy it would be to shake up the meta and allow a support to be paired with any role.
Why does it make any sense that supports be essentially a slave class dedicated to just one other class of champs, ADCs? Used to be that supports like Lulu and Soraka made more sense supporting an AP laner, Taric or Alistar were more suited to rocking the Jungle, and Morgana was one heck of a bully paired with a top lane bruiser.
Now we've got carries who are more than capable of surviving a farm lane solo, mids who can waveclear with ease, and supports who'd love to see play guarding, say, a vulnerable tank or melee carrying a duo lane. Braum/Yasuo can face down and beat up the nastiest ranged toplane harasser you can throw at them, yet they aren't allowed to leave bot and they get nothing but nerfs when they do.