From unofficial sources it seems like it was announced that Johnny's World will return at the end of the current year. Honestly I am not surprised as I had a feeling that this would happen when the show was first announced. Very rarely does Johnny Kitagawa introduce a new stage and just do it once, and I doubt that this show, which seems to be what he wants to be his magnum opus be a one time deal. Especially not with his talk of wanting to bring it overseas.
While no cast has been confirmed I am sure we will get the same groups, Hey! Say! JUMP, A.B.C-Z and Sexy Zone to be in it.
From what I have seen of the performances from the Shounen Club performances of them and from the Johnny's World documentary that was streaming on the net recently, the show seems to be a mess. Almost all flash and spectacle with not much of a coherent story to tie it all together well. So my only hope would be that the story gets some work for it to make a bit more sense. But then again it is a Johnny's musical and they really are not known for their great stories.
Outside of that as long as HSJ release a couple of CDs between the end of this Johnny's World run and the next I will be happy enough. From what I have heard there is at least one HSJ song from the musical that sounds to be at least B-side worthy for a new single and when they go on the 2013 year end music programs I would like to see them perform a new song instead of having to fall back on Super Delicate again. Because that would be beyond sad.