So it could be Slug Sage Mode, or Byakugou.
Either way I hope it is something we can all enjoy.
Here is one that's more interesting, but is a video.
I also believe in this theory , that Naruto will unlock the powers of the Rikodu and the Rinegan and he will also be the one to revive everyone that dies in this war , but this is a rather long term prediction
As for the cover , I'll be the overly optimistic one and say that it will be either Sakura solo with her new power or to take it even further , MinaKushi with NaruSaku combo color cover