Forms are good to learn the technique, and the proper stance, ect. of it, but sparring does the same. Sparring just further refines a given technique to the point of being able to apply consistently against a resisting opponent. I feel that some forms work should be done before sparring, to give a student at least vague feeling of technique before trying to spar. (sending a student to spar without first showing some techniques is asking for them to windmill the arms)
Forms are just an easy way to show techniques.
"In choosing your dwelling, know how to keep to the ground.
In cultivating your mind, know how to dive in the hidden depths.
In dealing with others, know how to be gentle and kind.
In speaking, know how to keep your words.
In governing, know how to maintain order.
In transacting business, know how to be efficient.
In making a move, know how to choose the right moment.
If you do not strive with others, you will be free from blame."
-Lao Tzu, Tao Teh Ching
An eye for an eye leaves the world blind.