I have watched Joel Osteen's show a few times. When I watch him I can't help but wonder about cloning and transmigration of the soul. Think about it. Splice Martin Short and Matthew McConaughey and infuse with Robert Schuller.
A Christian sermon should be the gospel, the good news. The centre of the good news is Jesus Christ. So, Jesus Christ ought to be the centre of the Christian sermon. The centre of Joel Osteen's talks is not Christ Jesus but Joel Osteen. His talks are full of good advice much of it useful but rarely is it particularly Christian. Joel Osteen is full of good advice, if you want to be like Joel Osteen. The typical model is humorous and "encouraging" anecdotes (usually involving CEOs), a Bible quote, a joke about his marriage (so, the camera has reason to be on his wife) and common sense.