This is my hoped for ending. The legend of Batman ends and the real legend, the greater legend, of Bruce Wayne begins.
Bruce has it wrong thinking symbols are incorruptible. Symbols are empty and can be filled with anything; they're highly unstable. But a man, a man is real flesh and blood and when it stands for something, it lasts, not like a symbol, which can undergo a change in meaning
Case in point: Harvey Dent.
Bruce will realize his mistake and that his only chance to help gotham is as man, with will, with fire (the fire rises for man, not a symbol).
That will be the end of batman. The legend ends. The real hero begins.