If you mean the church on air, i.e. the one whole church made of all believers of Jesus Christ from all corners of the earth, then my answer is that the church lack nothing because all that is necessary for her growth is being provided. God is in the inner room (heaven), Jesus made the way (Luke 23:45), The Holy Spirit leads us to Him(Rom 8:26,27), Ephesian 2:18.We all know the Church is not perfect , and we need to accept that fact.
Just a quick question
What does the Church lack ??? in a general sense..
I'm not sure if you are referring to any particular church (or denomination),
but, "What does the church lack?"
Nothing. The Church is whole and complete, ordained by God Himself.
What may be lacking inside the church?
Clergy who are sincere and dedicated to serve.
Clergy who don't practice heresy and sin themselves.
Laity that actually have a desire to know the real God.
Laity who are not there every Sunday just for show.