Next-gen gameplay is stuff that wasn't possible last-gen; larger multiplayer matches, emergent/player-driven scenarios, more dynamic environments... And on and on.
I realize you're being facetious but it doesn't take much thought to locate areas in gameplay where the ante can be upped solely due to more powerful hardware. And it's no controversy to say that the gameplay found in this game would have been possible in the last generation consoles. Or at least, I hope not.
A majority of that has already been done. We've already had randomly generated environments(no man's sky, bloodborne's chalice dungeon), dynamic destruction(Red faction, BF) and higher multiplayer counts(GTA5, Dark Souls 2, BF4/HL)
But nobody really sees these things because that isn't what they are looking for. "Next gen gameplay" is something new never seen before. And that can only be accomplished by the developer to build something creative. The hardware will help, but its usually the least important thing.