@Craig...I don't know if it would be a daring idea if they made Ali the main character and heroine. In fact in thinking about the generational aspect of these movies I think it is perfect sense. The first one gave us Katie and Micha who were a young couple in their mid-twenties. The second movie introduced us to Kristi and her husband. The third has gone back into the past when the girls were little and shown us their grandmother. I think it is a perfect theme to have Ali be the central character in the fourth film. Hitting all of those age demographics.
I can't think of anything else with regards to resolve the main arc. Ali and Hunter are the key to breaking this demonic pact. I am sure of that. I hope Peli and the screenwriter will recognize this fact as well. They're at a crossroads. Do we reward our loyal audience who have made these films possible by giving them a payoff to our original story line? Or do they risk alienating them with another story line? I also hope they bring back the directors for the fourth.