This is probably an impossible feature because of how 3ds Max is built. But I'm gonna ask anyway :D
One of the things that bugs me with the Material Editor in 3ds Max is that you can share maps across multiple materials. But there's no way to share values (as far as I know) - Even though sometimes you would very much like it to do so. Like f.example when using CoronaTriplanar or Corona AO in multiple slots, for gloss, diffuse, bump etc, you sometimes want them to behave the same, and it gets tedious having to apply the same values at multiple locations. Especially when working with a ton of materials and do a lot of tweaking. It would have been awesome with the ability to link a value the same way you can link a color which can be used across multiple slots. So that f.example scaling of Corona triplanar, or the Corona AO distance or directionality etc would share the values across all the parts of the material.
Like this:
https://www.dropbox.com/s/lyrmjac3in5vk2w/unified%20values.jpg?dl=0This would also be very useful in lets say the materials that comes with corona material library, since you usually have to make rather big changes in the materials if your objects sizes and looks are different from what the materials are intended for (and it can be a bit confusing to make big changes to a material someone else set up)
Just a thought :)