What if Tailwind applied to Zephyr and not Janna?

So the idea is that she gets Zephyr (the elemental, not the ability) at level one and allies walking towards Zephyr gain bonus Movement Speed. This could include Janna when she turns around and if Zephyr behaved similarly to Lulu's Pix, but it needn't. She also could gain the ghosted effect that Zephyr provides once you've put a point into it, which is usually around level 3, but she needn't either. Then, if she uses her W on an enemy that enemy gains Zephyr like how enemies gain Pix and allies gain bonus Movement Speed when walking towards them.

These are all buffs to Janna (buffs she doesn't need). However, they are buffs in the form of additional utility added to her kit. And as we know from Riot, additional utility makes balancing champions' numbers easier. So with these additions, Janna could be balanced more easily instead of just getting her numbers nerfed slightly every time she's too powerful.