Is it normal for a crew to come in from out of state to work on the track because of roughness complaints this close to opening? I genuinely don't know, maybe one of you enthusiasts know more. I'm just very startled by what I've found out.
No, it's not normal, but it's also not surprising and not anything approaching a disaster.
This discussion just needs context. If you have ridden a new B&M from the last year or two, you very much know what this "new B&M rattle" is. It IS a thing and I do think it IS an issue—but probably not in the way that someone who hasn't experienced it yet would immediately think.
When people who haven't experienced it hear "new B&M rattle," they reasonably assume we're talking about, say, the rattle of an Arrow Corkscrew or Vekoma SLC. This isn't that scale at all and,
even if it were, thanks to modern trains and restraints, the rider experience would STILL be night and day vs those older examples.
That being said, anyone who tells you the "new B&M rattle" doesn't exist is also massively exaggerating in my opinion. There is a VERY noticable difference in the smoothness between B&M dives from a few years ago and Iron Menace. Iron Menace isn't at all uncomfortable let alone even remotely painful, BUT it rattles and shakes in ways that previous B&M products and some current products from other manufacturers just simply do not.
B&M is no longer selling the Rolls-Royce of roller coasters. Their coasters don't seamlessly glide through the air anymore—they don't feel almost unnaturally glued to the track these days. They jitter, lightly rattle, and even occasionally nudge their way around their courses now. They're not running as smooth as the smoothest new Intamins, Vekomas, etc, but they're still infinitely smoother and more comfortable than lower-teir manufacturers and most anything from any non-B&M manufacturer 10 years ago.
To put this solely in the context of KD, I think you should expect Rapterra to be smoother and
notably more comfortable than Dominator, infinitely smoother than Flight of Fear, and more comfortable than Twisted Timbers. It won't feel like a the glass smooth gliding of a new B&M hyper from 2018 and that, in my opinion, IS a problem—but not because the coaster will be bad or even notably degraded, but because it harms the previously immaculate reputation and prestige of B&M and it feels like a cheaper product even if the experience overall is still very, very good.