My knee-jerk reaction was that it was a terrible score that was surely based on reviewer bias and was a perfect example of IGN at its "finest".
After I calmed down a bit and remembered that I'm a Pokemon fanboy who's more biased that pretty much anyone else in favor of the series, I came to see the review as just a bad piece of journalism. The final score doesn't even really bother me that much, and although I certainly think her negatives held some merit, the rest of the review just wasn't up to par with what we should expect from one of the biggest names in gaming journalism. Plot details, such as how the games would integrate the Emerald plot into the remakes, were scarce. No mention of the new mega evolutions and how they impacted gameplay. No mention of the robust post-game and how it offers an insane amount of replayability, especially when compared to X and Y's lackluster post-game.
Also, it's difficult to justify a 7.8 based on two "negatives", especially when the wording of one of them was of very poor choice. I don't know if the writer was just inexperienced or not, but it's hard to believe that she didn't know she would catch internet hell for all of this.