A few years ago, I had a freelance job as a writer on a kids TV series. It was good. It was cute. It was fun. Usually when you're brought onboard, they send you the bible and all the development material, model sheets, sample backgrounds - whatever they can to help you get the feel of the show.
As I was reading through the material, a few story ideas came to mind. I wrote them down so I could finesse them to pitch later. When I pitched these ideas to the story editor - he stopped me. The only pitches they were accepting were based on the 100 or so "story springboards" listed in the back of the bible. These had been written about a year before, when they were selling the series.
"Odd", I thought as I flipped through the bible. Not all of the story ideas from the pitch bible were great. The story editor actually liked my ideas better - but the producers insisted that we follow the bible exactly, as that is whatt hey'd sold to the broadcaster.
This raises the question - what exactly is the show? If you look at the production of a episode - you start with the script. (Okay, there's the pitch, premise, outline and various drafts - but we'll call it "the script". The script is what the show is all about.
That is, until you've completed the storyboard. Then you throw the script away - because the storyboard is closer to the final vision of the episode. Likewise, when your animation is done - the film becomes the document. You use the storyboard to aid in assembling the rough cut - but once it's done, you work from the film.
The Pitch Bible is a SALES TOOL. You use it to sell your show, then you set it aside as the show evolves. Maybe some things are working and others aren't. Maybe some characters are easier to write for - or become more popular. Maybe new and better ideas come up. The point is, if you lock yourself to the bible - you lose the opportinity for the series to grow.