Hi, thanks for those ideas, here is few responses:
- Palette box will be in the next version (tomorrow, I think)
- There is an experimental version for the color picker through transparent part of the canvas (right-click on the color picker icon to activate it, can take few seconds)
- if you hold left click on pen icon, you could have a line tool (buggy but will fix in the next version)
- importing things is a good idea, I write it in my to-do list. For now, you can paste an image from the clipboard if you want (I try with an image copy from photoshop, it's work)
- I asked myself the question for the onion skin, but I was thinking this is not really usefull for rotoscoping, is it?