Most of their negatives are inward facing. My fear of them taking the mantle of world power would be that they become a highly racist and destructive expansionist power similar to the US of the Manifest Destiny era, but that remains to be seen.
They are still quite openly repressive and you can and will face prison time for wrongspeak. Everything we hate about corporate surveillance they've been doing basically since the internet went mainstream. I doubt LGBT+ would have a good time under their rule, to say the least. Porn is outright criminalized. I'm not sure where they stand on piracy, but the tools you need to do it "safely" are probably illegal, and you've got the great firewall to contend with.