I am not the type that believes Genius just up and vanishes. Therefore I don't think that Jay-Z, one of the best lyricists of ALL time can hide behind the excuse of "nothing left" to rap about. I think that the bolded would be an excellent move for him. Yes, he did attempt to do it a little on Kingdom Come and stumbled, but he could learn from that and put together a pretty epic conceptual album with that theme.
I'll never believe that he's lost the capability to make dope albums, he's too talented for that. I DO think that he might've lost the "itch", which is a shame because I use to love looking forward to a new Jay-Z album