I don't think we'll be getting much information about Shoutarou's back story at all. He's probably the part I dislike about the show the most, at least a good majority of the time. I get the feeling that's supposed to portray the "eyes" of the viewer in that his connections to the whole Gaia Memory thing aren't as strong as Phillip or even Akiko, but because there's a lack of...well, any real reason to care about the guy, I find it hard to like him. Most of the time it just seems like he's "there" with the story happening to everyone but him, sure you have things like the Beast and Begins Night stuff, but that's just a small portion of the series.
It almost feels like there's something that they wanted to do with the character, but just never really got around to. He plays the detective, but...that's really it. Most of the time he's just investigating stuff, and there was a lot of promise in his character in the first five episodes or so, but after that he just became such a static character, which is fine at times, but the early episodes of the series gave me the impression that his outlook would change somewhat. Shroud calling him bad probably just means that she sees him as weak, and the reason he'll bring down Phillip is because he'll be holding him back, which, again, fine and dandy, but Shou is just such a boring character most of the time.
I'm pretty sure I went on a tangent there, but yeah, I don't see anything much deeper being revealed.