When you are watching a sporting event, there should be multiple channels of audio, each focused on different aspects of the game. Some of the announcers should be professionals, but some should just be enthusiastic fans who can say anything without worrying about preserving their relationships with players & managers.
Now, a few old guys announce games. They have cozy relationships with players & owners, and with the media that controls the rights. They usually stay on way past their prime, and younger, better guys can't get in.
They can't criticize players or managers, because the player might refuse an interview later. So you never hear which players are being lazy, who is going to be forced into retirement, or about which managers are really good.
They can't criticize owners, or the media, because they might lose their job. So when an owner is being an idiot, you never hear about it from them.
They can't talk deeply about strategy, cause that might turn off some of the viewers - so discussion always stays shallow.
If a fan runs onto the field, they can't talk about it, because that's against the rules - wouldn't want fans to know about it.
They can say anything they like, and focus on any aspect of the game they care about. They don't have to lie and say the game is interesting when it isn't. If a player is being lazy, they can call him out. If two players don't like each other, they can point it out. If a manager has an exploitable weakness, they can talk about it, and bring up other times he's done it. They can even make predictions on what's going to happen.
There'd be a channel with two pitchers, talking about pitch selection and the mental games going on between the hitters and the batters. Before every at bat they'd talk about what's gone on in the game until now - what strategy is the pitcher using vs this batter, what pitches the batter is looking for every time, etc.
There are so many specialized players in football - linemen have their own little games they play every down, that announcers rarely talk about. Football is way more complex and interesting than is allowed to go out over the air. The particular relationships between opposing players are impossible to cover now - but I'd like to hear about every matchup between a receiver and his defender for an entire game - as they got to know each other, how did each adjust over the course of the game? Did they start bluffing each other, and did they figure it out?
Are two things I love, and this would let so much more of that get out.
It wouldn't even need to be fans doing it - just a larger variety of free commentary on stuff would help.
With streaming it's not technically hard to do this today - but it's hard to aggregate your listeners, because it's probably not legal. So if you created a site where this happened, and it worked, it'd get attacked.
There are already piracy groups which upload sports to bittorrent. Those guys just need to hook up with fan announcers, and add alternate soundtracks, provided by different announcers. It could work. The only problem would be getting clean game sound - and that could be a deal breaker. You need the sound of the basketball bouncing to really get into a game. But maybe there could be a way to digitally remove the sounds of the normal announcers, and use the main soundtrack.
Each game could be issued with 10 different fan commentaries, and you could try them all pretty easily while watching. It wouldn't even add much to the soundtrack, either!
Another way would be to record it actually at the game, and then when you got home, put the sound your recorded over the video from tv. It'd give you the feeling of really being there!