This is yet another schedule limitation that's been around for years and years and still causes daily frustration. Door schedules are the perfect use case, as mentioned by a lot of other users. We can only schedule the material name, would love an option to also pull the material mark (or any other field).
I get that there might be technical limitations as we're asking it to schedule information from inside one of the reported fields, rather than just reporting a field that's directly present in the scheduled element, but could there not be a way to create a sort of calculated parameter, that functions only on Material Parameters? That way we could schedule the material (name) in column A as normal, and then in column B we could create the "calculated parameter" that has a function of "=column A mark" (or "=column A description", etc.) and then hide column A.
To my understanding this is basically what some people are already doing with dynamo scripts, but it's a rather complex workaround, and not in real time, and having the functionality built in would be a big improvement imo.