There are major events that could be set in motion, if they want to take that path. However, I do feel that there are a lot of stories to be explored on the micro level before it is necessary to go to a macro level.
Also, there are the possibility of events that could have world-shaking consequences if things go wrong that may be completely unnoticed if things go right. For example, in Raiders of the Lost Ark, who knows what might have happened if the nazis had somehow been able to turn the Ark of the Covenant into a weapon? No one, because they didn't, and it disappeared into a warehouse never to be seen again. Following the pulp tradition, an evil mastermind or mad wizard could come up with a scheme that could threaten a nation, but if you stop him , the public will never know.
As your characters attain higher levels, there will be epic challenges to face. And if WotC wants, they could certainly push forward a hard timeline with world-changing events. But I'm in no rush to see that happen. I'd rather let players explore the world and get to know it well before forcing major changes on everyone.
What does everyone else think? Personally, I would rather see a book that discusses War in Eberron -- the how to handle skirmishes or renewed hostilities between nations, how a major war might be handled, the military tactics and strengths of the major nations -- than a hard "The war has begun again" that may invalidate prior suppliments. This would provide the tools for a DM who wants to set off new wars (large or small) without forcing all people to go on a war footing, which may not suit many campaigns.