Material modifier per object

Hey! Would it be possible to have a master material modifier for objects? Like a 3ds Max modifier to change materials? And to be able to add a coefficient or arbitrary value to all the material channels of objects? Darker, rougher, less IOR, more opacity..? It's really handy when you get an object at the last minute & need to adjust its 50 materials.. And even to reduce the IOR of Cosmos characters.. Any ideas? Thanks! 🙂