Artemiy from Sinevibes here. Wanted to address a couple question here directly.
Regarding randomness - the plugin is actually build upon randomness. Each grain has a random size and is randomly positioned within the buffer. So each one ends up playing a different number of cycles per second. Moreover you can use "detune" to also apply speed deviation between all grains. And in addition to that, disabling "high density" also randomizes grain levels. I am not exactly sure what else you want us to randomize
Regarding movement - we have tried a few ways to add additional motion of grains, but it badly clashed with our implementation of the speed control. Speed is motion too, so having two sources of grain playback control just makes it very difficult to calibrate to be an exact ratio. Having this tape/vinyl-like control that's super smooth and is exactly a certain ratio was no. 1 priority.
All this said, our R&D never stops!
