I cant really say that too concretely, not until I beat the game, but from my impressions now, it seems to have some decent replayability. Maybe not something you can do over and over, but it shouldnt be a one shot game. There's the Play as Evil deal, where you choose an area and fight as a few different enemy sets (including Moria's Balrog) and spend time anhilating your usual party.

I dont think there will be a whole lot of plot twists except for in character development, considering we all know the story pretty well by now. But there's already some interesting things going on within the party, so that should prove to have some neat twists.