Something I suspect would be fairly simple to implement and I would really find helpful would be to have a few more options for color tinting the nodes. I've attached a super quick mockup (I didn't have time to make them perfect) just to give you an idea of some of the options I was thinking about and a few changes to some of the existing colors. I'm only suggesting this because I've found a few instances when making complex composition where a few extra colors would help make organization better.
I was thinking a total of 10 visually different colours would probably be sufficient. I'm really hoping this is something simple enough that votes aren't required because I've used them up on other requests. ;)