What was Tywin's plan for house Lannister and Casterly Rock?
Jaime's in the kingsguard so he can't take it, Cersei's a woman, and it'll be a hot day on the wall before Tywin willingly lets Tyrion inherit Casterly Rock. He doesn't remarry after Joanna passes, and it doesn't seem like him to let his brother or nephew inherit the rock. So what was his plan for House Lannister and Casterly rock?