I know that my preaching has improved over the years. I also know that my preaching is sometimes better and sometimes worse, for a whole variety of reasons. But what about the preaching of others? Many people will naturally evaluate the preaching of others, while some seem insistent that to evaluate is to somehow question the sovereign empowering of God.
I don’t deny that God can work through strengths and weaknesses in a preacher or sermon, but that doesn’t mean strengths and weaknesses don’t exist. We all know how God sometimes chooses to use our weaker attempts to do powerful work, but surely we mustn’t therefore pursue poorer preaching that grace may increase? No, we have to balance the matter of being a steward of the opportunity we have. A good steward will give their very best, but a humble steward will know that it is up to God to bring the increase.
I don’t deny that God can use all sorts of preachers in different situations, but that doesn’t mean the leadership in a church or event shouldn’t evaluate preachers. Again, it is a matter of stewardship. If I am a leader in a church and someone is invited to preach, I should be evaluating them prior to inviting again (and to be able to follow up with the people in the church pastorally). I may choose not to engage in a criticism-fest with others, but my responsibility as a leader is to evaluate, to guard and to feed the flock under my care. As I heard one leader said once, “I can’t play the piano, so I don’t.” It isn’t helping anything to give all preachers some sort of diplomatic immunity.
I don’t deny that different speakers appeal to different listeners, but that doesn’t mean that all preaching evaluation is purely subjective. Some things are not subjective. A speaker either preaches heresy or borders on it or is basically biblical or is solidly biblical . . . it may be a scale, but it can be evaluated. A speaker is either comprehensible or not (even though incomprehensible speakers are still a blessing to some diligent listeners who will get something out of whatever is spoken to them). But some things may be subjective, such as manner, tone, level of interest, relevance or connection. Having said that, such things can still be evaluated. It may have connected with me to a certain extent, but would it make sense to a visitor, to a non-believer, to person X or Y or Z? It is possible to have certain criteria by which to evaluate, depending on the nature of the meeting.
Preaching is sometimes described as both art and science. As art it is subjective, but as science there are means to evaluate preaching (and even art can have to pass certain standards to make it into a gallery!)
Biblical Preaching 
Jay Adams said, no two people in the crowd of people will hear you the same when you preach or teach. You might think they are hearing what you are saying but generally they only hear what they want.
What do you believe.
I would essentially agree with Jay Adams on this. It’s a simple matter of communication models. The receiver decodes the message sent, and will do so based on a variety of factors, including their own value system (which means they can reinterpret what they hear, or just shut it out if they want to do so).
I would like to know the context of what Jay Adams was saying though. Even though there is massive subjectivity, I hold to the fact that there are aspects of preaching that are somehow objectively evaluable (if that is a term). I suspect he wasn’t writing in respect to that issue.
Preaching is about inspiration, content and delivery. Unlike a secular speech to a secular audience, preaching has an overlay of the Holy Spirit. As such, what ultimately happens is guided and informed by the Divine. As such, preaching is Spiritually subjective.
“That sermon was for someone else” is occasionally heard as a result. Translation: It didn;t work for me but it may have been profound for someone else.
The quality of the content works objectively. Lousy content is always lousy. Bad exegesis, inept examples, poor jokes, all work to kill a sermon. The same goes for mediocre content. This guarantees yawns and shoulder shrugs.
Lastly, delivery matter objectvely depending on the audience. A charismatic congregation will not respond as well to a heady sermon. A heady congregation will resist animated sermons. They will – subjectively – evaluate the sermon based on expectations and custom.