I think she will receive some nerfs. However, it's mostly because people don't know how to play vs her, and the Lethality item changes riot is making, and the fact it'll take awhile for people to stop spamming Yasuo when they realize Yasuo can't block Senna.
Her scaling in range/damage is practical, tbh. The real challenge is when she is played as adc, and her support is a Taric/Sona/yuumi, who synergize symbiotic shields/heals. Her own heals/shields take a lot of mana to use and she can't realistically maintain them. But when it's a duo lane.... that's hard to deal with.
In other words, if they nerf her, I'm expecting a nerf to Mist spawn rates as an adc to encourage her to support (and not Mid)
P.S. Ekko is FAR FAR more broken right now.