Well, hmm. When I do fan based RPs I prefer two different tracks. One is the "From another point of view". In an example like this it'd be say, plaing out the War f the Lance from a group that is effected by the major events, at all the big battles perhaps, not the heroes though and might be a very different sort of team. In particular in War settings I often like do to the Common Infantryman type storyline. No legendary figures, no dragon lords, or epic level archmagi, etc for player characters. Gives a very different view of things and interesting in its own right, at least to me.
The second would be to avoid any preestablished stories at all and instead go with a new adventure. I'd prefer nothing so earth shattering that the fate of the group will determine the very shape of Krynn and the like. I like RPs with goals in particular. The "Sit around and talk everyday" type RPs get old for me. As long as there is some goal, som purpose out there to keep it moving forward rather than same ol' same ol' then I can keep going.
Even if I know that it could never be achieved.
For example in another RP I was in I was playing a genocidal warrior, seeking to save humanity by killing every single thing not human. And human by his definition as was handed down from his superiors. I knew I could never achieve it. At the very least because every other player, well, almost, in the RP was "Nonhuman" and they had strict "You can't kill my characters" plot armor rules.
But I could still cause a lot of trouble along the way. And knowing that, despite being destined to failure because I was the only person willing to let his character die or get maimed at all, was all I needed.