You're not wrong in what you say, but oh man. It goes far, far beyond XII in its sparseness. I'm still a fan of that game despite its many flaws and the way the plot lost its way towards the end because they still had a fairly reasonable balance of gameplay and exposition. But the meat of XV's story is reserved for the wikia page.
Gonna make two other unfavourable comparisons to XII while we're at it. Firstly, XII had one of the all time great localisation efforts. XVs is merely adequate. Secondly, the hunts. They felt so much more special in XII, which is kind of ironic considering XII was the one trying to be 'like an MMO' but XV was the one that ended up with 'kill X of this monster that is all over the place anyway' missions. The hunt that stands out in XV is Deadeye and I am utterly convinced the only reason that exists is because they wanted to make an exciting demo.