I don't think this is already on the roadmap but if so my apologies. It would be really handy to add tinting to display objects, so that you could call a method like graphic:tint(128, 255, 255)
I don't know exactly how things are setup under the hood, but I'm guessing every display object is a polygon for OpenGL, in which case it's pretty simple to just set vertex colors to tint the graphics.