I like the idea of showing Anakin's full journey, as the OP said.
But if going for Episode 3 only, then maybe the "Hero's Fall" journey could have some early stages before JKA has a token square off with Sidious, before they both go against Mace in the next stage, then using a bundle of clones as support characters when wiping out other Jedi Knights. But that has to be the end to get "Darth Vader (Unsuited)", as a final 1 on 1 stage with Kenobi just gets us "Crispy Vader" with his "I Hate You" basic attack....
Struggling as to where to squeeze in Padme as the arena is really covered off in her event, but maybe they can repeat that for an early stage?