From what I understand, the instrumentation won't change from the Cincinnati production, but I suppose things could be tweaked, especially considering Doyle's habits for change. The arrangements are, in line with the production's entire aesthetic, pulled out of the 70's. They are absolutely beautiful, completely re-done from scratch off the piano score.
The show is very intimate, but in a different way than was Sweeney. Sweeney had a lot of broken fourth-wall, and the whole very meta concept of the actors almost continually facing outward, rarely speaking toward their castmates. Company doesn't really have that element or degree of rigidity which made Sweeney as performative as it was. The show's "concept" is centered around the idea that Bobby is surrounded by various influences and those looking into and judging his life, so to speak. So in Cincinnati, it was done on a thrust stage; the orchestra surrounded him horizontally, as did the audience, with seating on three sides. On Broadway, the concept will literally be flipped on its head. A set piece with "bleachers," for lack of a better term, is being built, and he'll still be surrounded, but from a different angle. That may make it more ideal to see from higher up, but I don't think you can know one way or the other without having a look at the set piece. Because of its intimacy, I've voiced a lot of concern about the transfer from thurst to proscenium, but it sounds like they've got an interesting idea for how to keep the intimacy intact.
There are a few lines throughout the show that might make you go "... huh?" but under the assumption that the show is more "timeless" than it is "updated," those things never struck me as a big problem at all.
I hope you like it, Auggie! :)
A work of art is an invitation to love.