[eterps]

I don't care much for the eye candy either, but I do appreciate how gradient borders look:

https://cdn.imgchest.com/files/y2pckdepoa7.png

That's the only eye candy I would wish for in Sway or SwayFx.

[bee_rider]

There’s a 500 line script called “xborders” that will draw eye-candy borders on i3. By default I think it does solid colors, but it is 500 lines of Python, I bet you could customize it to draw whatever gradients you want. Needs a compositor, of course.