@RiotRepertior: You seem to be on the right path with this (Prototype-Kit Review)

First of all, that passive and the grounded-effect. Absolutley genius! That No-Boots-Thing should be introduced to more champs if you ask me, maybe even with some variation (like an unique item like Viktor has? Would at least fit Nami...)

However, as it is in this current - of course very experimental - iteration of the kit it feels more like some kind of gimmic while at the same time you seem to cling too much to the current version of cassios kit. Here is some advice: DO NOT FALL INTO THE SAME TRAP LIKE STASHU. Just because the reworked kit is seemingly as close to the old version as possible does not mean it's good. If anything, it appears half-assed and does not really solve the basic problems with the old kit.

Another problem is the ultimate: I still don't think that it fits with Cassios theme. Don't get me wrong, petrification is awesome and DOES belong to her, but the way it is applied does not. If it is kept like this, she will always be "that medusa-ripoff-token-character" instead of "Cassiopaia". It would make for some awesome poison tho - one that first slows and the longer you stand in it you feel your body slowly turning to stone... Just something to think about^^

Right now you seem to have the problem that you have to keep twin-fang and Q as primary damage sources while the W+R are utility supporting that.

However, I claim that there is no need for a truly dedicated damage spell in her kit. You could simply add the following line to her passive:

"Cassio's abilities and basic attacks deal bonus damage on poisoned targets, increased for every individual poison the target suffers from."

Like that you do not need an dedicated high damage spell. You could simple have three more utility focussed basic abilities that, when used all together, become really powerful. And since I am a player who absolutely despises the machine-gun-playstyle I would have absolutely no qualms for Twin Fang to be removed for the sake of another poison. Also, this change would increase the synergy with other poison champs (like Singed f. ex.), giving her an extra individual reason to be picked in certain teamcomps.

But overall you seem on a good way with this kit and I approve of it. Also... could we please have more of these "accidental leaks"? The feedback you will get from them will be more valuable than dozends of hours of internal playtesting I guess...