The Max Landis pitch if you haven't read it...
http://www.maxlandiswrites.com/ghostbusters-iii/
Remember this was just a pitch, and there is no actual draft or script of this. What could have ended up on the screen or the script itself would probably have been vastly tweaked here and there. That being said, I personally think it was a great idea, and probably one of the better one's that would have worked as a direct sequel. Definitely has some of his hipster shit in there, but also a lot of good ideas.
The idea of Ghostbusters ending up becoming a global franchise just seems like one of the roads if very well could have taken after GB 2, and just seems like an idea that makes sense and easy to swallow.
The Pitch is a little more than him just giving his fanfiction idea online. He actually pitched the idea to Sony, who loved it, and all he had to do was talk to Reitman. If Reitman had said yes, then Landis would have gotten a shot at the script. The meeting never took place because Feig had come in and already snatched up the reigns.