I suspect the statement,
"We'll be seeing a lot more passenger injuries"
was made in reference to the possibility of increased wake turbulence encounters due to the reduced vertical separation, which may or may not be a valid concern. That aside I can tell you that most folks in the States don't consider the introduction of RVSM as a big deal, most operators that cross the Atlantic or Pacific have been working with it just fine for years. The only ones complaining would be the operators of older jets who had to shell out upwards of $200,000 per AC to get them in compliance, and even they should get a return on their investment with the fuel savings.