Why not create a stacking buff with draw that gives 1-2% of let's say increased healing, and stacks up to 3-5 times (depending if it gives 1% (->5times); if it gives 2% (->3times)) on a duration that barely suffices. Like 32-35sec (server lag might need to be taken into account). Therefore one would encourage players to use draw on CD.
Edit: rephrased stuff :o
