I think it's time for them to just move forward with this thing. Not forward as in production, well I guess I mean that to, but forward as it just moving forward with the story. In other words, a new group of Ghostbusters in a movie set in the same universe as the other movies. A reboot/sequel if you will. Stop waiting around for the old cast to get older. Have Aykroyd and Hudson return in the most minor of roles, have Potts return, and definitly pay Moranis anything he wants to return. Have either one or two older actors play Ghostbusters to show that this thing is still going on, perhaps they were there when the old guys were still going. Then have 2 new younger actors who'll play new kids on the job. My pick for a cast would be Woody Harrelson, Donald Glover, Emma Stone, and Danny Mcbride. Ok, the first 3 are set in stone for me. I can see anyone filling the 4th pick really. To tell the truth, Matthew McConaughey was my top pick, but then it would be True Dective reunion(not a bad thing). It's also a Zombieland reunion. Still MacConaughey has a lot of range, and I easly see him filling Murrays shoes......or..... Have it remain the first 3 actors, then at the end we get our surprise 4th Ghostbuster, Murray. I'd get him to come back for a small role. I like the trope that the Ghostbusters end up in the Mayors office each film, and it's hard not to see it being natural progression for Peter Venkman to become Mayor of New York. They convince him to return with the notion that a Mayor with a low public rating, can suit up one last time and save New York just in time for re-election. A raise of the eyebrow later, and a quick cut to the exact scene with a now Older Venkman yelling out the car window,"Come on, lets see some lights," and then definitly have "Saving the Day," playing with police escort. That is all... Do feel free to add your own ideas for a possible GB 3.