So, what if Victor Grishin became the General Secretary of the USSR instead of Gorbachev? It's highly unlikely a Third World War would've occurred if Grishin had become GSCP instead of Gorbachev. There's nothing to indicate Grishin was a madman, and peace between the United States and USSR had been maintained for the 40 years since World War II.
There's no reason to think the massive American strategic nuclear arsenal wouldn't have continued to serve as a deterrent. As for Glasnost and Perestroika and conditions in the USSR at the time Gorbachev assumed power, in the words of one author whose name I can't remember, "The patient was chronically ill, but it wasn't the disease that killed him. It was the treatment the doctor prescribed."
Then again, an eventual collapse could have been far more unpleasant, even barring a nuclear exchange. Also there would be very interesting effects of a longer lasting Cold War. I don't know if the USSR and the rest of the Eastern Bloc could hold out another decade, but if it could the world would be a very different place.
However, Grishin was very corrupt - they called him the Godfather.
What do you think?