Children's books and board games? Interesting. Actually sorry no, no interest in those unfortunately. How about merchandising something the players who know the brand already (ie the only people who would probably care) could appreciate?
Interesting. I can see your logic - basically, sell more random stuff to those who are already D&D players. Which they do, to an extent, such as with special miniatures and collector's books and other stuff.
But I think in the long run, expanding the brand is a far better approach. Children books and board games to get new players interested, and part of the gaming community, rather than trying to milk existing gamers for all that they've got.
I agree that they shouldn't be as frantic over piracy, but... I don't think that is the only logic in play, either.