Now, to the dark ages comment. It was a rejection of the Greco-Roman views and policies, where it became more important to be spiritual and the arts became less important. Religion made a thrust forward and with 'big brother' now no longer watching your every move each country took it chances at gaining new territory.
The Fourth Era is supposed to reflect the dark ages, if one accepts that the Empire is a reflection of ancient Rome. What were left with is a similar situation: The lingering remnants of the Empire are like the Western (Holy) Roman Empire which keeps the capital. Then there is a separate empire born from the separation of the original, the Eastern Roman (Byzantine) Empire, which seems like the Thalmor. Like the Byzantine Empire in history, I think the Thalmor are doing pretty good, while the Empire itself is crumbling (which is one of the plot elements in Skyrim)
I think the end of the Oblivion Crisis was the last act of the Third Era, actually, not the first of the Fourth.
The final sequence of the events happened all around the same time. It was so close and sudden I doubt it matters much. But I believe it can technically be recorded as a Third Era event, because time was still measured in the Third Era while it was happening. The Fourth Era, when the world is really different, happens when the crisis is over. But the end of one thing is only the beginning of the next. The Fourth Era started with the Oblivion Crisis; they won't just wait for another notable event to come along to "kick start" the next era.
The world of TES isn't our world. A good example of how more 'civilized' the society and people became in LOTR in time, which was, in order words, nothing. The LOTR "society and people" actually degraded from their old and magnificant civilizations for thousands of years.
Ken Rolston, up until Skyrim, was one of the lead developers at Bethesda. His method was to make everything an anology to a real-world example, and in a lot of places he made it happen like that. It's not our world, but it's a reflection of it. It can be argued that most games are, I guess. People can only build off of what they know, and you can only make reality differ ever so much from what we have on earth. But that's just basic stuff, like the sky is blue, the trees are green (and that there are trees in the first place), people walk on two legs, and gravity pulls you downwards.
Okay, so we see a decline, I was trying to get at what you all think will be the changes, other then dragons of course. Such as different types of armor weapons, etc.
We'll see new armor and weapons for sure, every region has something unique. But we'll also see a return of the things we're familiar with. Daedric will still be the best material anyone can imagine, Glass, Iron, Ebony, Steel, and Leather will still be tried-and-true materials that are good for making armor. You can go from Rome to Persia, and their armor may look different, but they're still made out of the same sorts of material.
The end of the Empire marked the end of order. Now we have chaos and wars. A pretty relevant thing.
War in Skyrim at least. But that war is being caused by the fact that the Empire
isn't dead yet.