I propose that on another level, at least at some times, it is a good thing for us to be discontent. Many times in the bible we see people expressing their discontent with the injustice and evil and sin in our world. Certainly this is in line with God's perspective.
But there is yet another kind of spiritual discontent. This is when we are unsatisfied with our own spiritual state. We begin to expect more of God and, as a result, we expect more of ourselves. Discontent such as this drives us to vulnerability and to more earnest waiting on God.
In all of our spiritual discontent, I pray along with the apostle Paul in high expectation:
I keep asking that the God of our Lord Jesus Christ, the glorious Father, may give you the Spirit of wisdom and revelation, so that you may know him better. I pray also that the eyes of your heart may be enlightened in order that you may know the hope to which he has called you, the riches of his glorious inheritance in the saints, and his incomparably great power for us who believe. That power is like the working of his mighty strength...How have you experienced spiritual discontent in your own life?