I feel like I have a lot of things I want changed about the Appearance palette that cannot be done in the form of a one-dimensional list of effects.

I'd like to suggest something inspired by the "node view" in programs like Blender or Toon Boom or Unreal. Give me a 2d canvas upon which I can arrange strokes, fills, and effects, and let me plug them into each other in complex ways. Let me control exactly when a brush is applied to a stroke by moving its effect around. Let me dynamically generate an opacity mask for an entire object, and another one for three of the seven fills and strokes I have on it. Let me generate complex pieces of plumbing that do crazy things based on me drawing one simple path.

Keeping the Appearance palette around and adding a new Appearance Nodes palette would be fine. Or it could be a new mode in the existing palette. It's also perfectly fine if the existing Appearance palette can't edit Appearance Nodes and just displays a polite apology. There's a simplicity to the existing palette that might be worth retaining, I dunno, when it gets to the point of being in a beta, ask people how they'd feel about losing the old one, and be aggressive about hunting for ways it might break existing appearance stacks - ask us for our craziest piles of native and plugin effects and build a nice set of test cases!

I am probably asking a lot here. This is feels like a big enough change to be one of the top features of an entire release. Possibly even more. It'll probably involve changing some assumptions that are made deep in the parts of Illustrator nobody understands any more. And it's entirely for the most hardcore users, who're using it in the most esoteric ways. Good luck convincing the people who control the budget that a significant part of Illustrator's development budget for a year or three should be devoted to something that's got zero noob appeal.

But after about a decade of exploring its possibilities, I'm constantly butting up against the limitations of the Appearance palette. It's time for something to change. Maybe it's just time for me to figure out how to survive a couple months of zero productivity because I'm figuring out how to turn another, younger program into something I can whip out art even half as fast as I can do it in Illustrator. And probably get animation capabilities and some amount of 3d into the bargain. I dunno. I'm fifty years old and I've loved using this program as my main art tool for half my life. Change is complicated.