It would be interesting to hear from the horse's mouth (i.e. the designers) what the rationale was for the changes. I accept MadDjinn's analysis that it makes sense for pikes to be stronger than swords because of the difference in eras, but either way it's completely changed the dynamics of the early game. My guess is that too many people moaned that if you didn't have iron in Vanilla then you were basically doomed to a long defensive spell of turtling, so removing the iron requirement for cats and buffing pikes was seen as a way to make it easier for human players to play aggressive games.
If that's true, it seems like a bad reason to me, and it removes an important strategic dimension: if you don't have iron in G&K, then you don't really need to do anything special to adapt other than build pikes and accept that from muskets on your units will be starting without experience from pre-renaissance battles. And the fact is, as lots of people have said, IW is so expensive and CS is such an appealing tech for other reasons that frequently pikes are actually available before swords, despite coming from a later era.
At least the rare late game resources, oil, alu and uranium, can still be worth fighting a war for, depending how extensive your puppet empire is by that time.
I decided to do an experiment and go for iron no matter what in a game over the weekend, and it worked out pretty interesting. Ended up in the top-middle of a pangea map, with the only available iron in tundra near the south pole, separated from my capital by Bismarck doing his thing spamming cities and units like crazy, Babylon and Genghis. I duly planted a city down there (it didn't get a trade route till like industrial), pumped out the swords pretty damn quick, and had a lot of fun clawing my way through the ensuing mayhem to longswords and safety.
In vanilla, there was an incentive to do that kind of thing: now games have been homogenized - in honesty, it would have been a better strategy (and a more relaxing game) to forget about the iron, build pikes, and expand in a completely traditional way from my base.
