Being able to lay the healing done over the damage taken graph could be very useful from an officer standpoint to see how efficiently and observant the healers are.
Seeing big heals go off then a tank dies is one view.
Seeing the tank get heals BEFORE a big wave of damage and die while the healers are casting is another view.
Also seeing a healer using big heals during periods of little damage then go OOM during big damage points is something quantitative that that raider can be coached on.
I see this as a great learning tool by officers to train new raiders and for skilled players to find new elements to hone their skills even finer.
Graph Overlay
Re: Graph Overlay
This is currently possible on a given individual player detail page, though not for the raid as a whole.