I can tell you that it won't be done just yet. When Scott when on an interview I remember him saying that the only spoilers he'd give was that no one can copy and use the names "FNAF 3 and 4" so that pretty much sums that up. Plus, there are still so many questions to be answered. Maybe it will take a bit longer than the other games to come out but I don't believe it is quite over just yet.
I know, part of me is like that. I need to know! I wanna know what happened at Fredbear's Dinner. Scott did such an awesome job on the third one, taking time to make another one would make that one just as awesome!
I, personally, would really like to see the last game in a completely revamped style where you actually play through all the events which recurred. It would be so amazing to actually SEE what happened rather than all these speculations but I doubt that's what it will be like x3
I know, I really wanna know what happened in the very first restaurant. Part of me thinks it's over with, but the other half needs to know if there is more. I'm so tempted to try writing a story from the Puppet's view point, just my own theory/idea.