A drop down option for reflections like refractions on how it affects Alpha would be very helpful.
For example you could throw down a chrome ground plane and get the alpha of the reflected object as well which is something we do very frequently but would currently need to do in two passes: Reflection, Reflection of White Matte.
You might be able to get similar effect with the “Reflection occlusion” mode of VRayDirt and the “Affect alpha” option enabled. You can also use VRayExtraTex to compute this as an additional render element.