I usually use empty Assign actions, that don't do anything, labeled "NOP", to help me organize the flow in a action.
As a note, this doesn't have any impact in SU (Software Unit) counting because the Assign action is empty.
This solution works for me, but it would be more visually helpful if this specific action NOP existed and had a different image than the Assign image, something like a circle, in coerence with the triangle for the Start action and the Square for the End action.
Additionally, by default this action would be named NOP, but optionally the developer could change it's label to use it like a comment in the flow.
I sometimes need to add a comment in the flow, to clarify the functionality, but since comments appear in big yellow rectangles it's makes it difficult to organize the flow.
For instance, in Assign actions, the label can be a long text, that is truncated by Service Studio when displayed, but when hovering the mouse cursor over the Assign action the full text appears in a pop balloon, making it easy to read the full text.
As comment, the image of this action with be in yellow.
Besides, this doesn't seem to be very difficult to implement, as this NOP action is already very similar with the Assign action.