The ability to disable the onion skin on a specific frame while onion skin is on.

I have an animation with 10 frames. I want my last frame to match the first one. I don't want onion skin to be shown between 1 and 10.

Krita and TVPaint both handle opacity on each individual onion skin. I don't think this is absolutely necessary as long as we can easily switch on and off each individual onion skin.