The new Miasma is bad and doesn't make sense.
It doesn't give vision and it no longer functions as a self-peel or setup for Q, which Cassiopeia was heavily reliant on before it was changed. With these changes, she's being bent over by assassins and mobile melee champions even worse than she was before.
If you didn't play Cass before, or just weren't good, the primary use of Miasma was to either drop it on yourself after being jumped on, or drop it on a nearby champion to ensure they're slowed while your Q lands. The strong slow it gave allowed you to make distance and ensure you could get an ult off on whatever jumped you. If you tried to ult in place, good players would just step through you or into your model and completely avoid it.
This iteration is useless, except as a zoning tool. Even if you throw it at a champion who is at range and you expect to use some gap closer, they'll just blow their mobility towards you before it hits the ground, making it pointless.
Can this be fixed? I'd rather have some way to protect myself when an assassin or melee champion jumps on top of me.