Janna needs buffs (or a rework)

With the recent reworks to Sona and Soraka, I have to ask why Janna hasn't received the same amount of attention? Sona still has insane burst very useful auras and ult. Meanwhile, Janna's ult is the only thing she has. Everything else about her is mediocre at best. I'm not really sure what I'd do if I reworked her, but one thing I've thought about is her passive. I'm not sure exactly how it works right now, but I'm guessing it gives 5% MS regardless of where her allies are. Is this correct? Anyways, I would improve her passive to make it so when allies are nearby, they gain additional movement speed (increased to 10% for nearby allies for instance). What would you do for Janna if you reworked her? I love her concept but she is simply outclassed by other supports atm.