I was thinking today (my job is mindless, so I think a lot), wouldn't it be nice if you could choose the color of your hunters mark, via interface options? i.e. instead of red it could be a choice of red, indigo, purple, blue, cyan, green, green-yellow, yellow, yellow-orange, orange, or red-orange. Also, the debuff icon would represent the new color as well.
Not only would this permit people to have a "cooler" hunters mark (I would prefer cyan, other people may want to keep it red, others may prefer green for "go", etc), it would also allow different hunters to mark different targets, similar to the raid icons or the high-level mage polymorphs.
What do you all think? A simple addition, but it would be very powerful IMO.