In doing some "research", I had read that the producers had pre-plotted out the major events of the series early on. Is this not the case?
I don't know but I don't believe it for a second.
Fringe has been criticized by some for having too many monster of the week episodes that don't move the plot forward.
I believe the original plan from the writers was to introduce all the stuff from the season one finale in season five or something. Obviously, the audience would have lost interest very quickly by then so they had to push the plot forward.