It is true, when you are preaching, you are not doing a commentary on the passage. If someone wants to hear a commentary, they would go to the commentary. Preaching is about conveying a message from God. 

It is not a lecture. Definitely not, unless you are doing a bible study.

Interesting to hear local preachers who really are doing a lot of ‘lectures’ and ‘commentary’ and not a lot of preaching. 

Preaching is hard. Always have, always will be.