I checked the patch notes and realized that they left out Cass on the mana and mana regen buffs. As I remember Cass is pretty mana hungry and since mana pots have been removed she's been indirectly needed ( as if she wasn't bad enough). I opened this discussion wondering why riot didn't buff her mana or mana regens.
Because instead of buying mana pots, Cass bought Tear and mana regen items.
Riot hates Cass, there's no other explanation for this. She's been in a bad state for the majority of season 5 already and even after all that time they never considered buffing her. She's literally unplayable right now since pre-season heavily favors early game champs due to games ending after 20-25 minutes. You won't hit her lategame passive anymore nor will you ever reach a stage where you could even carry a game.
Also the overall nerf to ap-items made her life a lot harder, too. The same can be said about the buffs to mres on a bunch of other items which only serve to make mages obsolete.
One of the Rioters said something along the lines of this: (granted there are so many Red posts right now I can't remember where it was)
"Cass didn't normally buy two mana pots on average, it was less than the mages that got a mana buff."
I'll see if I can find the post and be more correct with my answer.
Edit:
Xypherous (NA)
"Based on our internal item purchase data - Cass didn't buy ~2+ mana potions a game which was our internal metric for mages to determine whether or not they used mana potions extensively enough to be heavily affected.
We didn't compensate based on mana consumption - but directly off whether or not they purchased it significantly."
were eall left out of the mana/mana regen changes. Riot probably forgot about them since they're not common picks anymore, besides Ahri and Malphite. =x
It is true that cassie can manage her mana through E, but that does not help in trading at all, if you waste your mana pool in one trade (which is not difficult and wont kill anyone) you'll have to be afk farming with E for a looooong time to get half that mana back, and you cant trade anymore before that, the enemy laner will probably sustain up with pots anyways. So yeah, cassio early and mid game can be stupidly weak, also, imo, Tear of the Goddess is a late game item, it really is not that good at sustaining mana early like 
. Problem with cassie imo is that her damage feels too poor compared to her manapool, if another champ like 
, etc... wastes its manapool in laning phase, the damage done would be way higher.
How many threads...? Cass didn't buy mana potions anyway, because they don't help her. She could burn through a full stack and not really be any better off. She bought flat mana, and conserved her mana until mid game when she could reliably kill someone without running out (which, again, mana potions did not help with due to the speed at which she can use mana; she needs a large mana pool, not regen). She is better at this now, because Q and W do extra damage thanks to Deathfire Touch, meaning she doesn't need to spam E to win trades. The Dark Seal and the new Mejai's Soulstealer help her a lot, too.
What kind of retarded excuse is that:
Cass doesn't use mana potions
or
It doesn't matter cause Cass buys tear
What the actual fuck? Cass is 1 of many champions made by Riot and even though they have raped her pretty hard, she AT VERY LEAST should be treated like rest when it comes to her main or second most important stat she needs to be even viable.
Lol "cassie". Funny way of spelling champion in need of deletion.
yeah she seems pretty screwed because she is a late-game champ, and most games just don't make it to late game on this patch.
tear is probably garbage on her at this point, better off rushing RoA and relying on E last hits.
better off not playing cass at all. tbh, but her E is still pretty cool to restore mana. if you really wanna play her, learn that, and stop complaining :/ grab the mana regen mastery :/
assie iso stashu
Cass has the ability to get mana refunded easily as well. Annie didnt get mana buffs either. stop shitposting already
