The simplicity of this approach is so brilliant that it just might work. That is-- assuming you only give sticky arrows to the (task) "lumpers" vs. the "splitters" around the office. Stripping down takes guts and discipline.
As brilliant and effective as my project colleagues are-- I don't think we could handle it. First, everyone would want their thing represented (and some would be persnickety about which color arrow they got-- you know who you are!). Second, I think we'd succumb to urges to put our recurring meetings, holidays, and happy hours.
It might be worth a try, though, on the next proposal. Unlike a lot of the projects we tackle, there is no wiggle room in the due dates and the color teams come, ready or not.
Worth a shot!