For a true finale he should release like a double CD of all the best unheard shit he has in his vault, for the fans.
Obviously that ain't gonna happen but I think it would be the best encore ever. All these mysterious tracks he has with Rakim and other 'amazing' shit nobody has heard. If he compiled the best of it from 99-? (whenever he quits) and arranges it chronologically like a story.
More than 2 CD's then. A box-set maybe. That would be class.