If you can provide me with sources that substantiate that claim then I could perhaps look into tweaking the next version.
http://www.britannica.com/EBchecked/topic/382397/military-technology/57567/Body-armour#ref=ref521908
-- States that bronze armour is easier to work with than iron, but is nearly impossible to forge into plate due to weight and difficulties in producing even thickness. It seems like bronze armour was used in conjunction with iron for a long time, though, but nowhere does it state that bronze is better or worse- only that it is sub-par when it comes to plate, so they are probably comparible until the invention of plate. Of course, dwarves use plate so this gets tricky and beyond the scope of DF.
http://www.fencingonline.com/academy/duelling_to_fencing.htm
-- Talks about the relative bluntness of bronze swords in comparison to iron swords. Is also an interesting read in general =).
http://books.google.com.au/books?id=GpVbnsqAzxIC&pg=PA1&lpg=PA1&dq=bronze+armour&source=bl&ots=EGM5eW-j7B&sig=fjY4nmgyELo019rvhbMtTylmZKI&hl=en&ei=vMH1SanpKaTk6gPLs4G5Dw&sa=X&oi=book_result&ct=result&resnum=9#PPA9,M1
Finally, best source I could find. An interesting book about how armour is made, and a few comparisons between the metals. Page 8 straight up states that, while iron was either on par or inferior to bronze initially, quenching methods eventually made iron harder and thus more useful in weapons and armour (although this was a difficult process). Earlier on it also gives a comparison between different types of steel and bronze, and makes references to several different types of bronze (annealed and cold-worked). If the dwarves are using primitive iron casting, they would not be using advanced (cold-worked) bronze either, and annealed bronze is vastly inferior to iron or steel.
It also states near the start that steel is by far cheaper than bronze,vastly stronger when quenched, and easier to create. Finally, in order to create wrought iron from pig iron you also need flux, but only in some reactions is the flux rendered totally unusable.
You're misled here - cold-working isn't more complicated; it's LESS complicated. Annealing the bronze would have been a later addition to the process.
Cold working a metal (almost always a non-ferrous metal, such as silver, copper, or bronze) just means beating on it with a hammer until it "work-hardens" due to the impact. It's actually a form of material fatigue, in that hardening makes it more brittle. You'll notice the same thing if you do something like take a thin piece of aluminum (like a cut-up soda can) and bend it back and forth at one "joint" (recommend pliers for this - the edges can be sharp). Quickly it becomes more and more difficult to bend, and eventually it will snap rather than bend any more. That's because the "joint" has been work-hardened by the stress. Less flexible, more brittle.
Actually, easier (and less sharp) is a paper clip. Bend it a few times at one point and you'll see it break leaving a sharp, less flexible, work-hardened point at the break.
Same thing would happen if you were to beat on it with a hammer, it's just less easy to see with such a thin piece of metal.