I had the first chance to try out the "planning" tool in MP in a 2v2 tonight and wanted to say what a fantastic system this is.....to be able to draw the lines, arrows and text onto the map (showing what you intend to do, or asking / ordering your team mate) and then sending it to them is really quite brillent.
It is also easy to use, although I'm not sure how you know you have a new message to check, we were using the chat box to say message sent. I need to read the manual again !.