The old Cassiopeia could zone out the enemy due to her passive that allowed her to spam Q's that actually did damage plus her W did more then just tickle enemies back then. Her AoE damage was what I found most appealing about her as a mage plus the benefit of them poisoning the enemy. Somehow Riot got it in their head that Cassie's E was what she was all about when it was all of her spells in combination that made her special. I have a feeling someone said "Hey why not make an scaling ap carry, super farming mage" and then someone else said "Well cassiopeia needs a rework why not try this out on her?".
Now they realize that no one likes this idea and whats more they test this idea by reworking a old and beloved champ and suddenly they're surprised at how much hate they are getting. The solution to the Cassiopeia issue is ....
-Learn from your mistakes
-and more importantly....fix them......soon......plz