What I would pay hand over fist for, is if we got legitimate STORY content. Not adventure mode, but expansions on the story mode. Naruto: the Last, Boruto the Movie, Naruto Gaiden, the Boruto Manga (even though that would sooner get a full game than an expansion), my point being there is a lot of content here for CC2 to play with. And plugging these into story mode rather than adventure mode opens us up to more Boss Battles and seeing these events with gorgeous cutscenes.
Not to mention that would give us playable characters such as the villains from said events, as well as legitimate playable versions of adult Naruto/Sasuke (not skins) with their own unique movesets. Apparently (I don't have a link to this, so take this with a grain of salt) CC2 went on record at one point claiming that the empty page in the character roster - you know, the page for DLC characters that only has like 5 characters in it and dozens of empty slots - will eventually be completely filled. So I have hope that maybe one day there will be DLC of exactly what I said above. At the very least the playable characters if CC2 can't be bothered to make expansions. But as it currently stands, the Sound 4 are too little too late and the other DLC packs are laughable.