If theology is the study of God and religious belief, then it would seem to make sense that those who pursue this study would have influence on the teaching of the Church.  
I disagree with you that theologians want to control the Church, but I believe that we ought to listen to theologians.  Most bishops, sadly, don't pursue the study of theology beyond undergraduate school.  From what I understand, most have graduate degrees in canon law.  It would seem to me that they would find it useful to listen to those who dedicate their lives to the study of theology.