The director Tetsuya Takahashi is not a person who will make a game which is MP focused without a story. There will definitely be lots of mundane MMO style fetch quests, because Xenosaga and Xenoblade had those too. They're basically the worst part of the game, and usually optional (but not if you're a completionist).
Monolithsoft's forte is in making large scale RPGs with lots of thought put into the worldview and locations, lots of history in the story, and quasi-philosophical anime sci-fi storylines. Also, this game will certainly have a bunch of HD towns and cities! Lol.
I mean even Borderlands 2, an extremely multiplayer focused game, had a ton of story.
Not only does story really fit with what Monolith does, it's becoming notably more of an expectation in games like this.