After seeming like a good idea to me at first, I think as nutildah says in another thread:
Yes, its already an overly complex system -- I agree that any additions would just create unnecessary complications. Some people continue to fail to grasp the difference between trust ratings and inclusions/exclusions, despite there being plenty of educational resources out there and years worth of banter about how they should be used.
I suppose that as often happens with certain ideas, in an ideal world it would be perfect, but implemented in this real world it would add more complications and problems.