BlitzkreigComin:
1. Snowball effect - fast wood pit = fast dock = more/earlier FBs = fast bronze with more food
2. Shang 1.0 - Most civs need 5 villies on deer (or berries) to maintain villie production. Shang's cheaper villies mean only 4 on deer (or berries) to maintain villie production. Persia's hunting bonus means only 3, so 2 extra woodies within those first few minutes of stone age while shang gets only 1 extra villie.
3. Shang 2.0 - An extra woodie for those few crucial early minutes means persia can get its docks up faster and crank out earlier FBs - let's say three extra FB over shang. Those three measly FBs gather 162f in the 3 minutes between 3:00 and 6:00, another 108f by 8:00 for a total of 270 extra food by tool. Add 50f from the gazelles and persia has 320f more than normal, while shang saved 210f on villies so persia is ahead of shang by 110f and three FBs at arrival in tool around 8 mins. Or if you stop producing FBs at the same number as shang, you're ahead 110f and 150w.
4. Shang 3.0 - The missing wood upgrades don't affect you until your opponent can research them, therefore I submit to you that persia's hunting bonus is economically superior to shang's villie bonus for at least the first 12 mins (or a minute after whenever your favorite shang opponents bronze).
5. Yammy 1.0 - In tool, yammy has cheap scouts and tougher scout ships. If both tool at 8 mins, persia (with *two* extra woodies early on, as yammy doesn't have shang's cheap villies) has +590f and +6 FBs - or you can build less FBs and keep the wood for scout ships, but persia's ahead in resources either way.
6. Yammy 2.0 - Persia, because of their extra food and/or extra FBs, can bronze first by 2-3 minutes. That means they can start making multiple TCs and boom woodies like mad. They can also have war galleys vs yammy's scout ships (and FBs) and cavs vs tool units (and villies) for 2-3 minutes.
7. Yammy 3.0 - Yammy finally bronzes, so now they get to make war galleys and cheap cavs. Persia however has camels and more woodies.
Don't worry about the rain Blitz, I always try to hold my (LAN?) parties indoors.
Note that not once did I mention iron in the above analysis. As I was telling Caesar_Constitine, persia's iron is just icing on the cake.