If I could go back in time and assassinate Gorbachev, I wouldn't do it. I don't think it's even arguable that the collapse of the USSR was a net positive for China. China sucked a lot of engineering talent from Ukraine and procured a lot of military tech they otherwise wouldn't have been able to procure from Russia.It's true, but Sino-Soviet relationships was already recovering by the time he was in charge. Plus collapse of Soviet Union has a lot of negative on China too. Overall I say jury is still out if you look at it from purely Chinese perspective and definitely way negative from Russian perspective.
Hell once upon a time Ukraine could build things like Varyag and An-225, now they're down to exporting wheat and women.
Now obviously the USSR collapsing was a negative for Russia, but I don't care about Russia.