So well I guess I'll post some "proof" about my experiences.
Mind you that I only played two games so I don't mean to say that this is anything conclusive, but you must start from something before we reach a sample big enough, perhaps someone else will follow after me.
Anyway it's not my habit to save often and to take screenshots so I'll use the replays.
This is my first game as Morocco.
As you can see in about 3 turns Shaka conquered two Assyrian cities. The war started at around turn 123, not exactly early, but not late either. Shaka obviously wanted to have his impi before starting a war.
Note also that for the most part there were no reasons to fight wars. I had no contested borders, Portugal was pretty much isolated, the Zulu themselves wouldn't have started a war if they didn't expand so quickly because their capital is on the western coast (BTW one of those cities is actually a conquered CS). The only ones that had a reason to fight were Poland and the Shoshone but they are both peaceful.
That city near the Assyrian borders was actually the last city I founded and the Assyrian were pretty much already busy with the Zulu by that point.
The last screenshot provides a proof that it wasn't a "quick" game, for those skeptics.
Second game as France:
This was actually supposed to be a "small continents" map, but I ended up spawning on a huge landmass for some reasons.
Turn 97 Assyria had already declared war on Brazil. That conquered city is actually Brazil's capital.
Morocco, Portugal and Indonesia are isolated. Shoshone and Venice are peaceful. Moreover the Borders between me and the Shoshone were full of mountains and a war on that front would have been awful for the attacker.
Anyway I DoW the Assyrian, and repelled them back with composite bow, swordmen and catapults.
Very rarely I fought wars with earlier technologies in my G&K games.
The last screenshot as usual provides proof that this was standard speed.
Later on Brazil conquered the last remaining city of the Assyrian (I didn't want to get the penalty for eradicating a city).
I conquered Venice encountering almost no opposition, and strangely enough nobody was really pissed about that.
Indonesia DoW on Brazil and conquered one of its colonies.
Brazil, Shoshone and Morocco then jumped in like vultures at the chances to conquer the remaining Venetian cities. They didn't put much efforts on that however as the war protracted for long without any conquest.
Brazil, Portugal and Morocco all settled on a free part of Indonesia's continent. Gahja Mada DoW on Brazil and conquered its colony.
At that point the Shoshone asked me if I wanted to Join them in a war against Indonesia. I had no interest in the land itself, but I thought it was a good idea to strengthen my bonds with the Shoshone and I supported them in naval warfare.
Indonesia in the end offered me a city in exchange for peace which I accepted because that city had uranium.
Portugal was my main enemy for the cultural victory and also the civ with the strongest army and technology. I chose Freedom and Maria chose Order. We've been at each other's throat for the whole late game.
We never went to war but I also never let my army fall behind hers.