What can be used as an alternative for Applesauce?
Applesauce has little flavor and almost no nutritional value. It is added to baked goods for the one thing it does have- pectin.

Pectin interferes with gluten in a similar manner to fat although by a different mechanism. For this reason applesauce is often used to replace some of the fat in recipes for health-conscious bakers. See this question.

Other banana bread recipes are very similar to cakes and rely on a huge amount of fat- often creamed with a large amount of sugar.

Your options are then to:


Replace the applesauce with some other oil substitute. Another puree of high-pectin fruit would work.
Switch to a recipe that just uses the fat and enjoy a richer banana bread.