I have become a huge fan of the compound arithmetic node, and there are a growing list of good ideas on this Idea Exchange that involve adding invert capability to more boolean inputs/outputs. Unfortunately, the circles used to show that an input/output is inverted are too small for my taste which makes them easily missed by the untrained eye. Filling the circles black is one possibility, but there is room between the terminals to at least double the size. With a more prominent indicator that a node is inverted, I will easily support adding invert capability anywhere it makes sense.
I know that most of the wildly popular ideas here involve making things smaller, hopefully with some of that reclaimed real estate we can make room for some slightly larger circles.