Is this going to work?

I don't think so.

Warner Bros wants to get directly to the consumer and bypass the iTunes store. But I am not sure that people will want to buy a new app for every film.

Yes, the making of looks great on the iPad, but it very dependent on the film. I'd like to see more on Batman or Hot Fuzz. But for 95% of the movies I see, I would want to see it first in Blu-Ray quality to judge if I want the extras. This must cost a fortune to make like this - only a handful of movies are going to make this worthwhile. If your bandwidth is capped, as it is in some countries, this is going to be a problem.