Well I would say that the scene where Xemnas and Xigbar discuss Organization XIII getting hearts and becoming Xehanorts is the scene i'm most interested in. Because I want a translation that explains clearly if the organization members spawned hearts naturally, or if Xehanort planted fragments of his own heart inside them and wanted those fragments to grow into fully fuctional Xehanort hearts. That is the most confusing part to me besides some of the time travel stuff.
The part of the game i'm most excited to play is probably either The Grid or the World That Never Was, probably the Young Xehanort boss I would say.