Ok, here's my idea for a new GhostBusters film.
It's been a few years since the events of GB2...actually a lot of years. The Ghostbusters have become a small franchise with a few facilities in a few different cities. Peter got hitched and is now taking care of Oscar with the only woman that can stand him...we get references to this in the film, but never see him.
Egon pretty much stays at the main New York HQ (which is where the film takes place) working on new tech. Ray and Wintson are assigned the duties of training new Ghostbusters to take over their spots in the New York facility. So, they take them out on missions and walk them through the procedures.
The film would start out with Ray and Wintson driving Ecto-1 with some new recruits...the whole thing is a disaster...no team work. The recruits are dumped, never to be seen again.
Enter the new stars of the series. We have the super smart, nerdy fellow who knows A LOT about pretty much any and everything, but lacks any and all street smarts. He's naive and very quirky. He occasionally works with Egon on new equipment...which is how he's picked up for the team.
Next is a girl. She loves this stuff. She can't wait to try out the new equipment, go on any mission she can get into. Backed with a tough new york attitude, mixed with a child-like awe and innocense when it comes to the supernatural and busting.
Then we have the cocky, arrogent ladies man. An asian fellow who's mainly in it purely out of curiousity. Much more intelligent than he seems, but prefers to play it dumb.
Last, but not least we have the by the book straight shooter guy. He's serious, with a hint of dry humor and cynicism.