Ivan Reitman quits ‘Ghostbusters’ sequel: What does the movie still have going for it?

A third “Ghostbusters” movie is officially on track to start filming sometime in early 2015, but already the sequel is facing quite a few obstacles.

For one, “Ghostbusters” co-star and co-writer Harold Ramis recently passed away. It goes without saying that a new film just wouldn’t be the same without the presence of the bookish Dr. Egon Spengler -- or without Ramis’s contributions behind the camera, for that matter.

Then there is the glaring fact that filmmaker Ivan Reitman (the comedy movie legend who directed the first two “Ghostbusters” films and one of the third film’s strongest proponents) quit the project this week in the wake of Ramis’ death. The director revealed to Deadline that the third film only featured the original Ghostbusters in very minor roles anyway, and that given recent events, his heart simply wasn’t in the film any longer.

Reitman will remain a producer on the upcoming film, but his directing was a key ingredient in the success of the first two “Ghostbusters” movies. Add to that Bill Murray’s refusal to be a part of a third movie, and the “Ghostbusters” reboot is looking pretty impotent at this point.

No Murray, no Ramis, no Reitman. What does “Ghostbusters 3” still have going for it?

Well, there's Winston Zeddemore, right? Actually, maybe not. Actor Ernie Hudson, who until Ramis’s death had been very interested in the project, recently told TMZ that he doesn’t think the third “Ghostbusters” movie will happen now.

“There can’t be a ‘Ghostbusters’ without Harold,” Hudson said in late February, calling the actor/writer/director the “glue” that held it all together.

So Winston is a big question mark. And even Rick Moranis said he would only consider coming out of retirement if the "Ghostbusters 3" script were really, really good.

“I wouldn't not do it, but it's got to be good,” Moranis told Empire in 2013. “I'm not interested in doing anything I've already done, and I thought the second one was a disappointment.”

But what about Ray Stantz?

Series star and co-writer Dan Aykroyd has been trying to get “Ghostbusters 3” going for more than 20 years now. He's been a driving force behind the many script revisions the project has gone through and in trying to woo his former "Saturday Night Live" cast mate Murray back into the fold.

That said, Aykroyd seemed determined to make a third film happen with or without the involvement of Murray, and doesn’t seem to have changed his tune in the wake of Ramis’s death, nor with Reitman’s pullout. While Aykroyd’s passion for the project is clear, what’s also clear to most fans is that a “Ghostbusters” movie featuring just Aykroyd and a new cast isn’t really a “Ghostbusters” movie at all.

For better or worse, Sony is pushing ahead with the project. If "Ghostbusters 3" has to happen, here's hoping that Reitman and Aykroyd can find the right director and cast to do the iconic comedy franchise justice.