I find her to be a waste of a ban and also a giant target for most supporting champs other than maybe janna or lulu. 0 mobility and 0 tank stats. Looks like the perfect champion to kill. Why is she considered strong??? She has lackluster peel for her adc too.
she can stand in the backline and keep her entire team at full health for an entire teamfight while being unreachable herself. her silence can turn easy escapes into unavoidable deaths, and if she does happen to take any poke damage she heals it right back with her Q. a 
with the positioning knowledge of an ADC player is effectively like being against a team comp that looks like this:
except one of those has high auto attack range and is building 
one of those has absolutely insane mobility and absolutely rediculous burst damage
one of those has an amazing initiation with massive amounts of CC
and one of those is actually
I can't really say much about how people think about her now, but...
Before her nerfs, she was strong, not in the doing tons of damage, having massive amounts of utility, having a hard engage sense, but more on how powerful her heals were due to the Windspeaker's Blessing mastery and how often she could spam it as the game progressed.
She just kept healing, and healing, and healing over and over again non stop. Reversing any pokes you do, any trade you make, all the burst you dished out, you could have killed their team 10 times over by now, but they remain topped off.
She will heal the hell out of her team mates non stop. Could have gotten a good wombo combo off on the enemy team, and she heals everyone right up after that
She stays in the back line behind the back line, having to go so far behind the enemy team is exceptionally dangerous, and she will build tanky at some point making it more difficult to kill her. A Soraka that has good positioning won't even let you scrape her.
Healers are one of the most annoying things in games that have PvP. If you can't kill healers and they handle themselves well under pressure while being able to keep both themselves AND their team mates topped off. Good luck.
I have played Soraka only once this season in Aram, and those heals she does in a game mode where you do 50% healing if used to heal a team mate are....damn....
but every single game i have with a raka i lose unless i get stupid fed and entire team rage quits. having to protect another champ is just setting your team behind because she cant peel at all. doesnt matter how much she can heal when they have a team that can ignore her heals and just go kill whoever they want
