Without revealing a major spoiler, Cersei will slowly do herself in by her own bungling as her Son, the King’s right hand. Its going to catch up to her as she realizes that she isn’t as wise or better yet shrewd as her father or anyone else in the Lancaster’s lot
Tyrion actually did Cersei a favor by killing Tywin. Now she doesn’t have to marry Loras. I haven’t read any of the books, but have been enjoying the series.