That’s interesting, as I actually disagree.
From my experiences (I’ve had 5 rides across 3 days in Alton Towers this year), I actually think Reborn has, if anything, felt faster than the original for me. Some of the turns have felt like they pack a bit more momentum than they used to on the original. Perhaps it’s just that having it gone for a year has made me appreciate what a brilliant ride it is a bit more now it’s back, but I’ve definitely felt like my rides this year have been a bit faster than my rides before the retrack.
When combined with the fact that the headbanging of the original is also gone, I personally find Nemesis Reborn to have improved on the original as a track and train ride experience, for sure. I personally find the rattle very subtle (I hardly even notice it) and completely benign, and am surprised it’s had as much discourse surrounding it as it has. If it wasn’t discussed as much as it has been, I don’t think I’d have even thought about it.