Dini wrote the whole thing. He's credited as the sole writer on the wiki page.
And it's nice that you picked out one generic piece of dialogue out of a 10-12 hour game, but that doesn't mean it was poorly written. If you think that's bad, wait until you hear the dialogue in AK, because so far, that's pretty much the standard of how Batman talks through the whole thing. I love how you said the setup is great, and hen go on to say the only interesting parts are "What's going on, what's going to happen, and why." like those aren't the top three ways to have people interested in where your plot is going.
I also don't know how you can say nothing consequential happens when the Titan formula finds it's way out of the Asylum, and multiple characters find their way out as well.