Not that she would kill innocent people.
Foreshadowing is not the same as having a proper and satisfying conclusion.
Well I disagree, during this season and the episode she started to see all of Westeros as her enemies. She was threatened and felt betrayed by everyone, she even said she chooses fear. She was also hungry for power and wanted everyone bow down to her. She was ready to burn the place down if Cercei didn't surrender and Cercei didn't. It didn't matter to her anymore when the bells were ringing, Cercei didn't bow down but killed yet another of her friends.
Her going straight to Cercei would not have been in line with her character anymore. Maybe a season ago before her arriving at Westeros but not anymore.