I think the problem with a lot of these roleplays, or at least the ones that I've seen, is that there isn't a skilled story writer as a sort of GM who dictactes where the plot goes. They would keep players from God-Modding and generally writing lame, lackluster crap like "I am doing nothing, waiting around for a fight." It's usually a GM's job to give players something to do, so that they aren't idle for too long. I mean, in a Teen Titan RP, have a scene where they fight, then take them back to the tower after the criminal is in jail and have them researching something or looking for something or having personal conversations that bring along the plot.
GM: Cyborg, you have found a strange mechanical device after beating this new villain. Now that you're back at the tower, you might want to take a look at it and see what it is.
Then they write how Cyborg would respond to see what kind of device it is and what he would say about it, but the GM would decide what it is, so that it is a surprise for the player. That makes it easier for the player to imagine Cyborg being all like "Woah!" when he finds out that the device is like some planet destroying ray or something.
But when you have a bunch of different players dictating where the plot goes, some players want to get with their favorite normal or original characters, some just want to fight other players, and some want to come up with their own stories, and all are making choices that make the story suck. If the GM was there to keep things from getting out of hand and telling people where they are and what they have just did recently to keep everyone updated, like every couple of days or every week, then things wouldn't be so chaotic.
Of course, I'm just guessing here. I've never RPed in my life before.