I did a couple more runs of 10 vs 10 battles just like last night. The naked dwarves with morningstars won both times against the full candy battle axe users, once with 7 survivors and once with 2 survivors. Unfortunately, I will have do some modding if I want to do weapon quality testing since vanilla arena mode does not allow for it. My guess is that weapon quality is where dwarven weapons will come into their own since most foreign weapons tend to not only be of low quality metal but also plain old low quality. I am very interested in seeing how masterwork steel and candy weapons fair against low quality foreign weapons. Anyway, one thing these tests do seem to indicate is that regardless of weapon material morning stars are very dangerous and if you find one of decent quality you should really hold onto it unless the thought of using the crafts of filthy undwarven craftsman is just too much to bear.
My experience with other foreign weapons suggests that many of them are very dangerous. It's not just the morningstars although I think they certainly rank amongst the most devastating options along with whips. The wounds the morningstars cause are just so nasty. While reading the though the reports a typical blow tended to include fractering or shattering the bone on top of several of the following: severing tendons, nerves, ligaments and opening arteries.
I'm interested in seeing how whips vs morningstars turns out next. Whips are almost universally believed to be OP by most df players. I want to see if they are really top dog.