Has anyone actually gone back through the various articles released by Lucas over the years regarding ROTJ? As far as I can remember, and I'll try to find an article to back it up, but Lando was slated to die in the DS battle whilst trying to escape. This is the reason why Han believes he won't see the Falcon again.
The original scene was to run as it does in the movie, but rather than shooting out of the fire like a phoenix, the flames engulf the Falcon killing the intrepid heroes. There was supposed to be a brief line with Lando commenting on how Han was not going to be happy right before the final explosion...
It looks like GL possibly didn't want a downbeat ending to his trilogy to contrast with the redemption of Anakin Skywalker, so 'saved' Lando and created his teddybear ending instead.
Like I said, I'll try to find an article backing this up, but it's not a new idea and certainly isn't Ady doing a GL for the sake of a big change.