Captain of LAX-SYD did that a couple of weeks ago. Gave flight details and told us about the other three members of the crew and their flying experience. It was a nice touch!^
I had the same experience, same flight about a year ago. I can also think of a couple of times on CO at EWR where the pilot took the mike at the gate to explain why we were running late and then take any and all questions.
I know some pilots are better in public than others, so it doesn't happen enough. But I would think that managements would encourage it. Someone speaking to pax in a straighforward way, and then listen, would go a long way to boosting customer satisfaction.