There is no end to reach without the story we're all following. Dungeons and trials are intimately related to what's going on in the story. They're not randomly thrown in. This isn't a fighting game or a racing game or some hack and slash that may or may not have a thin attempt at a story. This game is every inch a JRPG, just in an MMO skin. You cannot divorce the story from a JRPG without trying to turn it into something completely different and ruining what it originally was.