Like is riot willing to revert a change if enough of the fans asked for it to be reverted? Why or why not?
Clearly people want to revert Cassiopeia. Like has Riot thought about this, could it be a option ever? I know they stopped the Lee Sin changes but have they ever listened to any other group of players?
In the past, Riot has reverted basic champion mechanic and functionality changes at fan requests. Examples of this would be a change made to the movement of Draven's spinning axes, and changes to the targeting indicator of Varus's Q. More major gameplay changes are very rarely reverted.
There is a very small possibility for the Cassiopeia changes to be reverted, but before that happens, the changes will have to be put into a more balanced state that also addresses the feedback. Right now, two huge complaints about Cass are A. that she's weak and B. that her poison isn't a big focus of the kit. Both of these are fixable problems without necessitating a rework. Because the rework wasn't just made to appeal to Cassiopeia players (game health was also a concern), she's not going to be reverted without absolute certainty that the changes are completely unusable.
The Lee Sin changes were different. The only thing being added was some extremely unreliable late game power, and every aspect of his kit would have been subject to heavily increased counterplay with no gains. Ward jumping would have been all but removed. The ult would have done no damage unless you kicked someone through multiple people, which would have been very hard to do given that you could no longer Q into someone then ward jump into position (energy costs made it impossible). The Q damage was reduced unless you built very heavy damage. And in exchange, he would get more attack speed late game, and the late game attack speed is the single most boring part of his kit. Lee might need changes, but changes are not just "remove functionality until useless". The Cassiopeia changes at least added new things to do, even if they did leave her undertuned and unsatisfying. The Lee Sin changes didn't even try. If they had been added, it would have been the worst rework in the history of the game, even worse than the Cassiopeia rework and the first Skarner rework.
