Can Cassiopea Q leave behind a poison cloud for a few seconds?

Before the rework, Cass W could be cast upon her self and could have been used to bait champs into getting poisoned when her Q missed. With the new rework, this is not really possible anymore.

Would it be op if her Q left behind a poison cloud for 3 seconds. That way she can be a bit more reliable in poisoning her target and would have a better defense system.

It would also add to her poison mage aspect more.

Would this be op? She is still kinda weak on the pbe.