Board Thread:Manga/@comment-5184926-20150716034220/@comment-5774380-20150716134948

Remember that Isayama said that when he started Attack on Titan he had already planned how it was going to end, and that it was going to be a tragic finale where everyone dies; but he changed his mind due to the success of the series and now the finale will be different (and obviously we don't know how it will be). So it's very likely that in that scene Eren was having a premonitory dream where he was watching that finale and an older Mikasa saying goodbye to him before dying, though it is probably going to be changed in order to fit with the new finale.

About the title, I have always thought that the series will have an epilogue at the end where we will see the descendants of Eren from 2000 years in the future, either remembering the victory or the defeat of humanity, depending on what will happen.