Make it so that when you hold down a hotkey the colour picker is enabled, like in photoshop.

Would be very useful for pro artists, to go back and forth between for example the smudge tool that is on the second page of the tool bar thingy and the colour picker that is on the first layer. It just takes time, now that I think of it a hotkey for the smudge tool wouldn't be bad either that would be working in the same way. Because as a pro artists the tree tools you'd be using the most are the brush, the colour picker and the smudge tool.