Well, it would be fun once in a while if someone with the bank account of Bill Gates didn't give a single flying fuck and interfered in hot spots like Syria, and that doesn't even have to be military actions. A lot of problems in this world are just there because of the inactivity of nations. While the UN does nothing, hundred thousand people die just like that. Sometimes it would be refreshing if someone actually had the ability to shake these things up.
That's the essence of any super hero, someone who is not part of the same old ineffective and corrupt system and does the right thing at the right time.
Just recently I had a nice talk with my nephew. "Why doesn't Santa come to everyone's houses and take their guns away?" It would be so simple, wouldn't it? That's what a superhero would do. Like Superman single handedly got rid of all nuclear weapons in that one film.
I don't think nations would collapse because of that. I think most countries would start attacking that guy because, even if he was 100% good and always did the right thing, he'd be a great pain in the ass of the leaders.