I've been analyziing it in single player games
I analyzed the Why of it in single player, as that's the most easily repeatable way I could look at it at 3 am.
I'm opposed to rush play in general when it comes to civ, since that makes it play like some really poor RTS instead of a nation building game. Considering that FFH from all I understand is about nation building ( will your kingdom stand the test of time?) I think that encouraging the production of ten-15 units of the same type and going mongol on your neighbor is pretty lame.
I would think bronzeworking would fall into a builder strategy pretty early on anyway. Being able to remove forests (which I constantly seem to start with over 3/4 of my tiles) is pretty important. Getting axemen or even just copper for defense is a very useful perk.
Yes its worth it. Let's say you spend 60 turns building warriors. And 60 Turns building Axemen.
Warriors cost 25
Axeman cost 60
And let's say your production is 15 Hammers per turn. You would produce one warrior every 1.67 turns and an Axeman every 4 turns. This would mean you'd have 36 Warriors vs 15 Axeman. Upgrade the Warriors and you have 36 Axeman vs 15 Axeman.
Now let's say for arguments sake that you build warriors in 3 turns and Axeman in 4 turns, which sounds weird but I think I've remembered something similar myself. You would still have 25% more Axeman by building Warriors that way, and since Khazad has the Ingenuity trait, the upgrade is half-price and not too bad. I mean if you are gonna rush, you won't need to max research during this period anyways.
People, I really don't understand what you're talking about. Bronze working you'll get regardless unless you're elves, but even once you do, one has to carefully consider whether the training yard and the extra hammer cost is worth it. Warriors have 3 strength, axeman have 4, it's the bronze that gives it plus one. Warriors with bronze working in cities are fine, and with hammer advantage, might actually be at a plus.