I would like to see Shisui but that would seem like a plothole.
Manga stated that Shisui gave Itachi his remaining eye, then Itachi and Shisui faked Shisui's "death", as in they somehow made it look like he died by drowning himself in the Nakano river and made it look like both of his eyes were crushed so that a war over his eyes would not ensue. Then, Itachi said that Shisui departed and was never seen again and Itachi awakened his MS due to seeing his bestfriend in his last moments. Shisui commited suicide.
Besides, wouldn't it be a little weird if he was somehow still alive? He would have no eyes, so what use would he be during the war? And what would he have been doing all of these years? Shouldn't he have tried to stay in contact w/ his best friend Itachi, or his best friend's little brother, Sasuke?
So no. Shisui Uchiha is still dead and most likely not going to be shown alive and make an appearance, because it wouldn't make much sense, there's no reason for it due to him being no longer relevant, and the manga is ending this year so there isn't even enough time to elaborate on him.
However, I'm all up for seeing him in flashbacks again.
