Having just read that article, and I don't believe the author actually saw the tour.
I did just see it at the Kennedy Center this week, after seeing the show more than a dozen times on Broadway.
I was actually shocked at how good the sound was, after reading reviews and word of mouth from the beginning of the run stating otherwise. I was even in the rear orchestra, and still felt the show was loud, and well balanced.
What makes me most angry at that article, is that to say the kids have "accents" is nearly a lie. Compared to the Broadway production, the kids on tour speak with such a dulled down, nearly non existent cockney accents, it's hard to say that the accent is to blame for the sound issues. Those who have full blown accents, mainly Cassie Silva and Quinn Mattfield as her parents, were crystal clear.
I have seen many productions at the Kennedy center, sitting in various locations in the orchestra (front, mid, rear), and have never had sound problems.