This is a great question. If McDonalds were to introduce a new burger, they would need to do extensive research to ensure that their new product would be something that people want. In light of this, they can do several things.
First, they should try to find out what people are thinking in terms of their desires. In other words, what do the customers want? For example, do they want a cheaper burger, a higher end burger or something more healthy. If people are more health conscious, then McDonalds might want to introduce something that is healthier. They might offer leaner meat or whole wheat buns or even more vegetables. A veggie burger within this climate might be good.
Second, they should also see what other burger chains are doing. It is always good to keep up with competitors.
Finally, McDonalds, since it is an international chain, might want to also consider regional variables. In other words, what Asia wants might be different than what the Midwest wants.
You are so right on readerofbooks. I really like the idea about regional variables. There are cultural differences that would need to be considered. Also the idea about leaning more towards a health conscious audience might be a good idea. I personally would like to see them lean more toward that idea.