Tywin is genuinely a terrible politician. He’s like a crusader kings player who just does whatever the **** he wants and damns the consequences. And now his succession is completely ******, the realm is falling apart, everyone hates him, his house, and his bannermen, and the Red Wedding has ensured that there will be no mercy if they are to be defeated. Getting killed on the toilet is probably the best thing that could happen for his legacy, because it meant that Cersei is left to pick up his pieces and take the blame for his ********.