I always thought of the bartender as a human representation of divine intervention. He told Sam that the leaps were going to become more and more difficult. That means that he knew where Sam had been and where he was going.
I also loved the episode where Sam and Al traded places. I felt so bad for Sam getting the electro-shock treatment. Damn clever premise for a show.
They actually had planned to bring it back. A woman Sam had sex with in the evil leaper episode supposedly got pregnant with his daughter. She was going to leap and try to find her father. Glad they didn't do it though. That's a little bit too reaching. Plus, it's best to leave great memories alone.
Now if they had a two hour movie in which they finally wrapped it all up with the original actors, that would be great.