It's relatively easy to create an ambiguous character. Any conglomeration of likable and unlikeable traits, chosen at random, will result in an ambiguous character. Getting an audience to deeply identify with a character, on the other hand, is one of the hardest things in the world to do.

The best things in life don't come in adult sizes.

Give your hero a strong simple reason that he or she has to solve the problem right now.

It's relatively easy to create an ambiguous character. Any conglomeration of likable and unlikeable traits, chosen at random, will result in an ambiguous character. Getting an audience to deeply identify with a character, on the other hand, is one of the hardest things in the world to do.