I would like to have the ability to join a started game as an observer. I find that half the time when I get online, most of the players are already in game and I would like to watch as opposed to wait for the game(s) to finish.
This would probably need a game option to be enabled ("Observable") to allow it to avoid it being abused.
Would be quite cool if it were possible. I'm not entirely convinced it is possible, based on how it has to load up stuff etc, and that interferes with others... wouldn't it generate an out of sync error?