Knobs.
Just more knobs. There should be a knob next to every input that takes an angle value. The Scribble effect has one. The Gradient palette doesn't. The Transform palette has one but it could use another one along with a couple of text input boxes as an option to move an object a specified distance along a particular angle instead of moving it in X and Y. The angle value in the transform section of Properties doesn't have a knob. Scatter brush options have two horizontal sliders and no knobs. Put a knob next to each of those sliders.
Go through the entire UI and look for angle inputs that don't have knobs and give them knobs. And make this knob an easy-to-use component if it isn't one already. Astute's Phantasm Halftone plugin has an angle input with no knob. Make it trivial for them to fix this.
Also there's a bunch of feature requests for varying versions of "you can drag a number input and/or the arrows next to it and drag to change the value". Pick one of those. Make every input box work this way.
Thee's also a pattern where you click on a down-arrow next to a number input and a menu or slider drops down out of it. Sometimes you can drag and hold to go down it - stroke weight's fine for instance. Sometimes you can't - the opacity input box's dropdown gets you a slider, and you have to lift your stylus and click somewhere on the bar. It used to let you just click to bring up the slider, drag to a point on the bar, and release. It should still be doing that but this got lost in the UI rebuild like a decade ago and never came back. Find all of those dropdowns and fix that.

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I would not say there a re 'a bunch' of requests on scrubbing, I try to make them clump :)
I love the idea, respect the ferocity, agree with it, and want to add one comment — add knobs where there is a space to make one, and don’t do knobs like it’s done in Transform effect / Transform Each — occupying the full row.