Important to note that Bill Murray wasn't supposed to be in Ghostbusters to begin with. The Ghostbusters were supposed to be John Belushi, Eddie Murphy, and Dan Aykroyd, and Louis Tulley, played by Rick Moranis, was going to be played by John Candy but the role would've been a bit different. John Belushi died as the project was being developed and Murphy/Candy couldn't commit. That being said the revised and watered-down final version of Ghostbusters (original had them traveling through time and space, final had a more conventional science fiction story in NYC) worked fantastically with Bill Murray as the lead and Aykroyd/Ramis as the bumbling scientists. The problem with the upcoming sequel/reboot is that in between we had Ghostbusters 2 which, nostalgia factor aside, paled in comparison to the original and soured Murray on the series; so much so he won't even read a script for GB3. Aykroyd and director Ivan Reitman are going ahead with the third film in the series without Murray which is a shame but not unexpected. Harold Ramis is also attached to write and produce. Ethan Cohen (Tropic Thunder) is also writing. Aside from Murray, Rick Moranis is unlikely to participate as he's been almost completely retired from acting for several years. Moranis made bank from the series as well as Honey I Shrunk The Kids! and stepped back from the business. There was a rumour a while back that Seth Rogan and possibly other Superbad alumni were going to be involved as the new group of Ghostbusters.
