How transparent should pastors be from the pulpit?

Dennis Gunderson explains in this video that it is important for pastors to be transparent in their sermons but that they should exercise discretion on how transparent they are.

For instance, some pastors are too transparent in that their sermons become all about them. Sermons are not to be about ourselves entirely. There shouldn't be unnecessary distractions or digressions. 

Philippians 2:3 (NKJV) - "Let nothing be done through selfish ambition or conceit, but in lowliness of mind let each esteem others better than himself."

How often should a pastor include himself in making application to the congregation of matters of walking in practical righteousness? It's a hard question. I think some pastors have a habit of being so transparent that they're in the danger, unfortunately, of making too many of their sermons seem as though they're a little bit pastor-centric, and as though it's frequently quite a bit about them. Our sermons are not meant to be biographical studies of our own struggles, and so we don't want to overdo that, but there should be regular and frequent inclusion of himself as one to whom the word applies without distracting the congregation with all sorts of digressions about his own walk with God and as though this was something about him. You