I don't believe in a worldwide empire. The problem is that wars and occupation only fuel resentment and revenge.

There are two problems today IMO : inequalities and imperialism.

Inequalities is basically the western countries living on the exploitation of developing countries labour. The tendency is quite good I think though with the economies going back a bit to local production, it should balance things a bit if developing countries can catch up and stabilise.

Imperialism is very concerning though. The war for power between US and China can be very bad for everyone. Smaller countries or old powers refusing the evolution is the other problem.

IMO there is a paradox to see: bigger wars means that bigger nations are fighting, but they're going to stabilise ultimately. Europe saw wars for about all of history, culminating with the world wars, but ultimately the EU was born. I some way, the biggest the war, the biggest the place that get stabilised after that. Unfortunately it means some unfortunately big war may come in the future. But maybe the government will be reasonable at one point in front of the possible destruction of today's weapons.

To answer the question, I see a peaceful world as a big version of Europe : cooperation and no frontiers to build respect, friendship and human links, and a place for each country to be reasonably itself. There is a very long way to go though.