I find Azir to be super strong early game now, and I feel that he falls off pretty hard. Definitely not a hypercarry. Very different power curve than Cass.
I don't think Karthus can win games for you anymore. Not with the way League works today. Very easy to pop him and use one of your 18 dashes to get out of the defile.
These are all symptoms of poor balance on Riot's part. Those can be solved relatively easily. Azir was stated to being intended to be weak early and powerful late game, and it's easy to see that reflected in his play-style. They did smooth out his curve by nerfing his late game and buffing his early though. But with his minion mechanic, it's really hard to not make his late game monstrously powerful in terms of DPS (not so much at picking kills though)
To give you an idea of how far I'd push this, I think new Cass's kit could eventually be the first mage that can go duo bot in serious competitive games. Given a similar power curve as a marksman and her need for protection due to immobility and squishiness, it feels like we could make her a viable duo lane carry.
Does this sound interesting to you? Does to me, anyway. I really like the idea of breaking the strangehold ADCs have on the duo lane.
There's two things to point out here. Firstly, an AP+Support bot's already kind of a thing. Only issue here is that it's not been adopted by the majority who are still stuck in their rigid team compositions yet. Hell, sometimes you're even seeing an ADC solo-ing top lane. Sometimes you have a bruiser being supported, other times an AP.
And no, atleast not for CASSIOPEIA, I don't find that idea all that interesting on her. She really really doesn't fit the image of a hyper-scaling magical marksmen. If Stashu wanted that, he could have made a champion from the ground up to fit that image rather than aggravating fans who wanted Cassiopeia to fit her own image.
The fundamental problem Riot has is that old Cassiopeia didn't have a clear focus. The people that are unhappy now wanted her to focus on being a poison mage. As I've mentioned, what I want is for Cassiopeia to focus on being a gorgon, so I'm pretty comfortable with shifting power into E (although I wouldn't mind E being less powerful and Q being more powerful, either).
I think it's a very hard design problem to rework Cass. Comparable to reworking Karma, actually. I'm inclined to give Stashu as much support and constructive feedback as we can from out here, even though I know lots of people are going to inevitably be unhappy with the outcome.
Here's a glaringly obvious problem to Stashu and his approach to reworking.
Nearly all major reworks (Sion, Karma, Skarner, Viktor, etc.) have had developers gather feedbacks from the fanbase. Even future reworks such as Taric and Poppy have threads dedicated to them asking the fanbase WHAT THEY SEE the champion as and WHAT THEY WANT him/her to be. Taric has 3 threads! And even THOSE have been hit or miss! But at the very least there is communication going on.
In contrast, Stashu is only starting to talk about his rework AFTER the fact that he has all this crap done. He is only around AFTER he developed his fixation over this mano-a-mano brawler image. All this "communication" is only happening AFTER all he wasted all that time and resource to rework her into this obviously broken rework.
Asides from that, they didn't do an awfully great job explaining why she lacked focus, and that's partly because they keep coming up with new reasons why they wanted her reworked ("oh she's a lane bully! oh she was due for a rework! oh the Shurima even dictated she needed a rework!"). In this case, what is their exact claim that they thought she lacked focus? And what was their rationale in focusing on her most hated ability?
it's how Stashu is trying to gate all that power away from the lane phase
Which is really really stupid considering other hyper-carries happen to have pretty strong laning phase. Not Vayne who is legitimately weak. But look at Ryze who is a lane-bully now. Or Tristana with her powerful nukes. Or Kog'maw for the same reason (yet mechanically different) as Tristana. All of them also happen to have tools to keep themselves alive during their weakest phase too.
How receptive he is of feedback really depends on the end-product. But as of right now it's been questionable since the problems she's had since the beginning of the rework have still been present even in the current rework. And now people are beginning to grow impatient with each new update failing to address many of her problems.
Current passive works mechanically -- it's how Stashu is trying to gate all that power away from the lane phase.
Design-wise, it's stupid if the entire intention was to prevent the champion from being a lane-bully, which is 100% the reason why he did it to Cassiopeia.
But pretend that he didn't do it as a knee-jerk reaction to the fact that Cassiopeia can do what dozens other champions have been doing for a long time.
Thematically it's the opposite of what Cassiopeia should be. Xerath, Syndra, Kog'maw, or even Kha'zix, those are all champions such a Passive would have fit thematically with. Not a Poison Mage. Not a champion who have nothing to do with growing or evolving as part of their thematic structure.