Support mids should be meta now
I could never play Soraka due to her kit being hardwired to require allies but some supports like Sona can go mid and seriously mess up the enemy team. She'll never be able to burst like Xerath or even TF and mages counter her really hard, but in exchange she hard counters assassins similarly to how they counter mages.
Why? Because her Q burst is point and click so there's no shadow dodging or whatever out of her way.. She has a speed buff and her ult to get her under tower quickly (against Zed or Talon, they have to dodge by sacrificing a lot of their all in damage or their entire ult if they use mobility to get out of the way, so use it immediately after an all in ult). Even when the enemy gets her to half HP, she has enough heals in her first rank W with a full AP setup to get her back to full health before the enemy assassin, who's waiting for regeneration and other cooldowns, can dive again.
Supports also have at least one good ratio that's usually their main ability (Soraka's W, Janna's W + E, Sona's entire kit, Lulu's entire kit) in teamfights. Unlike assassins who have to rely on being able to kill one person then retreating before coming back to clean up which makes them fall off as it's inferior to constant damage from mages and marksmen, supports can still have utility thus letting them scale better.
Their weaknesses are serious problems against mages. I barely scraped out of lane against TF and completely lost against Cassiopeia. It's so extreme that I find it comparable to having LeBlanc dash into my tower as Xerath while missing then getting killed anyway. A support will always seem to have at least one ability that seems suited to just countering assassins and very little else (shields, silences, CC) leaving them with 1-3 abilities while most mages have 3-4 that are useful in such a fight. They also get hit very often regardless of skillshot vs point and click so a lot of the advantages supports have start to disappear. Then they get outscaled but not as hard as mages vs assassins if a mage manages to win lane.
EDIT: Zed mains gonna hate due to their experience against Zyra. When Sona, Soraka, Nami and Janna finally go mid, it'll finally be balanced and there'll finally be an end to the whole "mobility mid because everyone has skillshots" meta.