I'm thinking proliferation as positive. Just think of countries recently in war had nuclear deterrent. They might not have been invaded in first place. Everyone having nuclear weapons would make world much more peaceful and safer place.
That is unless we sanction all nations that have nuclear weapons and blockade them from international trade until they get rid of them and subject themselves to being open to inspections for couple centuries.
Then again the so called "rational" actors would be less likely do bad things. Just imagine how much better place world would be if in response to drone strike by Obama or Biden the NYC or Washington DC was hit by nuclear weapon. That would surely put end to those antics.
If you think the near-certainty of getting wiped out entirely at some point is the right price for avoiding wars, then sure. I'm not sure most people share that preference.
