Just make Yuumis E either a good heal or a good Movement speed buff...

Seriously, you are making noone happy with "Well, its a meh heal and a meh movement buff" approach, because seriously, the number of cases where these two actually work together to make this one ok skill are so rare, they aint even worth mentioning.

I understand when you dont like heals. Thats fine. She has a shield, that does the trick too. Just remove that slight breeze you call a heal from the spell, boost the movement speed and give it a decent duration and its in a beter spot than it is now.