I would love to see a system that adds clickable icons, or thought bubbles set with a pointer to any locations on the GM layers, opening up this clickabe icon or arrow would open something similar to a chat bubble with any given info you would like to add there, preferebly on a opaque black or white bubble with black or white text respectivly. Opening or minimizing the bubbles would allow you to open any relevant information on the fly without clutter by typing text on the map, maybe you could also add links in the bubbles to relevant handouts aswell. Why? Because making map specific notes is a troublesome process as notes have to be looked through in compendiums, opening up handouts etc, or by typing the information on the map itself, this however gets insanely cluttery and the background of the text falls into the background colors most of the time.