A Quote: Keep it simple and short!

[vit_r]

Animation writing should be short, because you have artists to fill out the visual details. Animation scripts are always too long and storyboard artists have to draw hundreds of extra scenes just to have them all cut out by the studio when they figure out that the show is too long.

Sometimes the whole show gets animated before the producers figure out they have wasted a hundred thousand dollars animating 10 minutes that doesn't fit into the half hour.

http://johnkstuff.blogspot.com/2007/03/writing-for-animation-keep-it-simple.html