Janna's Ultimate feels a bit OP

I know that a lot of people often say the reason Janna has high winrate is cause of her Movement speed and Shields. But I just came to noticed that her ultimate is just like a Fiora ultimate and Gragas ultimate combined. Huge knockback and Huge HoT. Idk about you but Janna has always been on high winrate even if her mobility and dmg got nerfed. Maybe she should get a rework overall? Since it's way to easy for a bad player to support with her while just pressing a button.

A bad janna could have between 3-5 deaths while a good janna never dies cause she support players without doing anything special. Even Soraka and Nami is way more complex than her. And at least their ultimate doesn't win games alone.