The strategy guide (in the Civ3 strategy & tips section) reveals much about the pace of the game, I think. Some of the previews gave a good idea of it too.
Especially the fact that cities are very tough to conquer, and that it is not unlikely for all starting tribes to make it through to the modern age, sounds very promising. And Jeffs remarks on the clashing of "well-grown" civilizations in the industrial age, after going through the distinct ancient and medieval periods, seems to indicate that each period have been given good attention to the kind of techs and units that are dominating. So that the different periods of the game will feel particularly different from each other.
I kinda like this attention to detail. But I do hope, they've left some of the freedom of Civ2 with the editor, so that you can scrap this "epoch"-playing if one doesn't like it. I think (in contrast to some of your posts here), that Civ2 offered a really vast freedom in playstyles, so you could get medieval if you liked, or rush through the techs if that was your game. I hope Civ3 will adjust in similar ways to the playstyle of the player.
The exponentiality of the unit stats speak their own language too. Apparantly the early game will be oh-so-slow as we know it, and the end game as fast-paced and destructive as ever, with a vastly improved midgame; medieval era and industrial-age. Remember, early research and wonderbuilding is slower than in the later eras. So naturally the pace of the game will increase, especially when the units gets dramatically more offensive, as we've seen!!