Feels like we're nearing the end. Soon granny turns back and she warns gramps about outliving the young ones and tells not to interact with the hourglass in their dream. Also it seems that they can keep living like this for an eternity.
I am more about the rune stones than the zombies. AFAIK we still haven't seen him using Beru's rune stone and then there is Emperor Hagrid-In-Chains he just defeated in Japan. This zombie business is getting boring. He needs some more tricks up his sleeve.