It is good to have a situation where there is interaction with the preacher regarding the message he has preached. One of the ways that this can operate is through having feedback. Sometimes this can be specially organised so that someone in the congregation is specifically given the task of completing a feedback form. This system can work well with the preacher being able to have a considered assessment of how he is preaching.
However, there is a potential problem and that is of preaching for the feedback. What I mean is that the preacher falls into the trap of preaching so that the feedback will be good. This is ever so subtle because you would expect that if the feedback is good then the preaching has been good. But it can be that the message has been mis-directed and has lost its cutting edge because the eye of the preacher has been slightly diverted.
When preaching, it is the fact that we are preaching for God and before God that should drive us. When we start to be overly conscious of hoping to get a good feedback report then we likely have lost, even if it be a small degree, our consciousness of God.
So feedback is good and is a most worthwhile thing to have. However, we do need to be aware of the potential pitfall of preaching for feedback.