Well, basically yeah. It didn't used to be a problem, because before you could argue that language changes naturally over lots of time anyway, so Rinoa merely changed along with the mainstream. However, since now the only way for R=U to work is by freezing down Rinoa, she'd wake up in the future still retaining all her habits from the games era, thus invalidating the argument.

One might argue that she hung around enough after being awoken in the future to assimilate the new dialect or whatever, but this is obviously an incredibly weak argument.