I really hope Olenna will have a scene with Cersei, and as Cersei will cheer for murdering her whole family and humiliating her grandson in such a tremendous way before killing him, Olenna will smirk, telling her she was the one who killed her firstborn son.
He sided with the fake Queen who killed his Liege lord & actual Queen (Margaery) and betrayed the woman he served his entire life. It was only fitting that he experienced his beloved house go up in flames with him.
And it’s hilarious that his house is now in Sam’s hands, the son he hated. Revenge is sweet.