Also I know that's how the writers went with DS9, but I think The Next Generation would have solved the Dominion War in one episode. That was their style after all. Probably through diplomacy or speechification.
The Dominion would have made for some lame villains if they could be convinced not go to war with one speech. Not all societies want peace, some want war. Chamberlain tried to use diplomatic methods to avoid a war with Nazi Germany and that failed completely. Diplomacy only works the other side isn't hell bent to start a war.