Swap inputs when connecting an input to an input
One thing that I am used to from other graph editors, which currently does nothing right now is when you select an input and then connect it to a different input, it swaps the connection - e.g. if I have a Blend node, and I've connected the wrong thing to the foreground and background inputs, it should be as simple as clicking those two inputs to move them around. Right now it's an error-prone and multi-step process to trace where the both the inputs are coming from, reconnect one (which deletes the other path), hope you remember where the other one was from, then connect that one.
Similarly, connecting one output to another output can swap those, which makes it really easy to iterate when, say, changing a mask that has being used by a lot of different nodes. Right now I often find myself needing to add a Dot node, manually reconnect a whole bunch of stuff to the Dot node's output, and then swapping the input to this.