Raindrops on water are distractingly unrealistic
Raindrops currently look like an expanding white disk, rather than like actual raindrops. This is because the math that's meant to give them a ripple pattern (the call to
sin()) is adjusted poorly for how their radius and such work.
Also, raindrops always appear in the same place, repeatedly, on loop. This is because the random adjustment within the raindrop grid is not time-sensitive, only position-sensitive. This makes it even more obvious that they're a procedural effect and not a physics phenomenon.
Making this issue to have an issue number to point at for a new MR I'm about to open.