You keep phrasing what you call the question as if God were going to come down from somewhere and run the government. That's not what's going to happen. A bunch of Taliban types are going to run the government on ancient sons-of-the-desert tribal principles.
The hypothetical question was asked in 1119. If you believe in God, why would you not think it "a good thing" for others to believe in that God?
I'm not talking about coercion here. SeaLion said it would be "dreadful" if other countries believed in her God.
Do you think it would be "dreadful" if everyone believed in your God (assuming you believe in God)?