A few things I think about the new cass

I got to play around with her yesterday and while I don't like losing power from poison, it's not the end of the world. That said:

1. I'm not entirely sure how the poison passive works but if you manage to both Q and W an enemy champ, I'd like to see a stack per tick of damage instead of once per second, even if you doubled up. If that's the case, I'd like the passive to be reworded.

2. It takes a very long time for her to build her passive. If operating by CS alone and making sure you both posioned a creep and CSed him, that's 40 minutes. From what others have said it takes about 30 minutes or more in normal game conditions to get to 400. So I'd like to see more gradual changes maybe every 50 stacks. Or you could make it so that champ kills and assists are worth more stacks.

3. Stacking your passive requires mana and her spells are expensive early on. You can mitigate by only last hitting with E once poisoned creeps are low. Still most champs don't use their spells to clear waves unless they need to. Cass HAS to use spells to clear waves constantly. I think her new passive has given her a toxic form of gameplay for the cass player. Why? Trading. If I start trading with the other guy I'm going to go OOM really quickly which means I can't CS in the way I need to after that.

4. Mana options for her are weak. Her E makes it pretty clear she wants seraph's embrace. However her passive gives her 25% cdr and her masteries will give her another 5%. So she only really wants WotA for the last 10%. This is something of an issue because she doesn't really need the CDR of athene's or morellonomicon, which are wasted stats on her. Sure you could go mikeals instead of WotA, but you'd be gimping yourself. Plus you can't just start tear and a chalise, you'd have no damage in lane making her weak early game weaker.

5. Once you've maxed your E, there's no real spike for Cass unless she can get to 200 then 400 stacks.

Of all the things about Cass's rework, I think the new passive is the most mind boggling. Don't get me wrong I love the power boost in it, even if it is too spiky. And I do think the stacking of the passive is a nice mechanic to play with. However I think it was created under a false assumption.

Her old passive was a noob trap and needed to go, but I think this one is just as bad. Here's why it's bad: it gives her weird gameplay. Now you can argue that it encourages cass to play like she always did. However Cass used to play by spamming her spells because her old passive enabled her to. While her E gives her some mana management, I think the pressures of her passive and trading make it insufficient for that job.

Basically her old passive enabled her old patterns, her new passive was designed around those old patterns, but her new passive doesn't enable her gameplay patterns like her old passive. So riot is telling her to play like she always did, but without the tool that let her play like she always did. While she might still be playable, I think she's going to have issues because of the new passive going forward.

I've talked about this in the past but Cass has the highest peak MPS in the game without considering ults. That's because her E acts as a massive mana sink when she starts spamming it. I think putting some mana management in it was a good start, but I think she needs more if you want to keep her old gameplay style intact.