A. Story, story, story and great images. A. Ones which are image based do very well. Too many talking heads hurt salability. No, not at all - but it's important to know that your program will eventually need to be reversioned for the French market, the Italian market, the German market, etc. Produce the story with good visual elements, along with interviews and sales will come much easier.
Broadcasters prefer to renarrate or sub-title themselves.
It's simply a waste of money. A. First, look at a five year term. Look up the 2000 Pricing Guide. If your subject supports it, multiple episodes can also increase earnings. An international television hour runs 50 minutes, plus or minus 2 minutes.