Juggling your Colour between your hearts and memory is made more tedious than it really should be due to the limited options you're given. It's just the very basic functionality: hold mouse button to pick up, click to put down Colour. A couple features I am missing:

- collect all Colour. With a shift-click you should be able to pick up all the Colour you're pointing at, instead of having to hold down the button until you've hoovered it all up.
- retain leftover Colour. If you try to fill a heart with more Colour than it can hold, the leftover should not be put back in your memory, so you could click on another heart to fill it with the same Colour right away.
- drain/fill similar Colour. Ctrl-clicking on a heart could result in all Colour of the same type being drained from your body. Could work in reverse, too, filling as many of your hearts with one Colour as it can, if you ctrl-click on your memory.

Is any of the above possible in the game? Or any chance it could be modded/patched in?

Unfortunalty I don't think it is possible ingame.