Some things I think you should look at.
First of all, GM shield – Give the exact same armor as crafted shields like Elven/Darkness shields. Due to the fact that they are INCREDIBLY rare shouldnt the armor atleast be 5-10 more in armor? That would atleast be quite realistic.
And about the prots that the gm shield got. Lets say I got Darkness Shield equipped at the same time I got Darkness platemail legs equipped and I change from the Darkness Shield/1-tile weap to a spear. Then I will lose the protection that the Darkness legs gives in necro protection.
I know that is usually the case when you got two things equipped and the other gives a higher prot, but should that really be the case when two items give the exact same protection?
I dunno really if my english makes any sense, but I hope so 🙂