The dithering patterns are in the folder when you download PixelOver (called dithering)
Maybe for picking color you could use comparison between views ?
Yes for bezier it should be improved to add curve visualisation.
For HSV, it is fixed since v0.14.2, do you use the latest version ?
All shortcuts are in settings/shortcuts : 
But there isn't shortcuts to go next/previous keyframes, I'll note that for a future update.
Dithering is well generated in realtime, what's make you say that ?
Maybe you have an input selected when you try to do the spacebar ? I'll double check on my side. Yes I hesitated about the playspeed because it override the FPS, but yes I understand, I'll keep it with the export (maybe an optional option "on" by default).