WOTC owes me nothing.
When I buy a WOTC product, I have expectations, and if they are met or exceeded, I consider the product of high quality and I am more likely to buy future products. If they are wise, they'll consider my feedback on future products, if not they'll produce stuff I don't want and I won't buy it. Each business transaction is its own, and since I have the ability to read reviews and flip through books before purchasing, there ususally aren't any surprises regarding quality.
Now if the binding on a book fell apart shortly after its purchase, I'd feel they would owe me a replacement. Hasn't happened yet to me, but I'll agree that for my money they owe me a certain level of quality, when it is something as objective as a book binding. If I've purchased something, and it doesn't meet basic, objective expectations, I would consider it a breach of contract.
With regard to content, they don't owe me a thing. A rule that turns out to be unbalanced, a class that is not fun to play, or a spell that is poorly written will make me more cautious in my next purchase, but I wouldn't consider that any sort of breach of contract. Art is subjective, and as scientific as we try to be about game rules, it's not a science. It's a game, not a textbook, and if people can't understand the difference, then I don't know how to explain it to them.
Not printing a book I want to see isn't going to bother me either. As much as I'd love to see a new version of the D&D Rules Cyclopedia updated to be a basic version of 3.5 D&D, I'm not going to say they "owe" it to me. If they "promise" to print it and then decide not to, I'm still not going to say it was owed. I know that if they don't, it was a business decision, and I want them to stay in business.
There are too many people in this world who think that everyone owes them something.