I wrote this stream-of-consciousness awhile ago on a different forum:
I: Anakin starts on his homeworld of Tatooine with Owen and Beru. Ben the Jedi (a general in the Alderaanian military) suddenly arrives (perhaps crash-landing?) and meets them (maybe for the first time, or perhaps he has returned, or makes "rounds" to recruit). During a short stay on Tatooine, he recruits Anakin into the (already-ongoing) Clone Wars by appealing to Anakin's idealism and sense of justice. The end of the movie might be the last battle of the Clone Wars, perhaps taking place over, on, or in some other way involved with Alderaan.
II: Perhaps there are 'security' operations going on post-CW (as the galaxy had been pretty well demolished by the wars). Anakin, as a Jedi Knight, works with Ben (and perhaps other Jedi) and sees the widespread devastation, perhaps through experiencing individuals' stories. Anakin begins to draw the conclusion that what the galaxy really needs is order. Maybe friends of his are or were killed, populations destroyed, worlds burned, and he - and the rest of the Jedi - aren't or weren't strong enough to protect everyone. In the distant core of the galaxy, Palpatine begins to rally supporters to set up a new political system (contrasting it with the 'weak' Republic). Anakin might leave Ben (and their group of Jedi?) at the end of the movie, going to the Core systems to investigate this new rising Empire.
Perhaps Anakin's leaving in search of "strength" might also have to do with an event regarding his wife's apparent death (after he leaves she's discovered to be alive), or maybe he just drives her away with his increasing militancy?
III: Anakin has become an enforcer (perhaps the enforcer) for the New Order. Ben, having drawn the opposite conclusion from the events of the Clone Wars (Ben - "wars not make one great" to Anakin's "bring order to the galaxy" by any means necessary) would search Anakin out. They might find each other relatively early in the movie, clash intellectually throughout, Anakin losing respect for Ben and the Jedi even more (for their 'weakness') and then the movie would end with the volcano duel. At some point Anakin would end up in a position where he would need Ben's help to avoid falling into lava or onto hot rubble. He chooses not to accept Ben's offers of assistance (he can't think of himself as vulnerable). If there's a "fall" scene in this version, it's this one. A physical fall as well as a metaphorical one.