So on my latest world I finally got attacked by Goblins (about 1.5 years in) and they completely demolished a 9 squad strong military, probably not all that surprising, some were proficient but most were barely through "basic" yet.
After the massacre I closed off the fort for about a year, waiting for the last members of the goblins to bugger off (I managed to catch about 12 that breached the retractable bridge in cages and happily disarmed all of them) I finally let everyone out to catch some fresh air, reclaim corpses, and any gear from the few goblins that actually died. They immediately ambushed again, a 12 strong force of assholes with bows, and a whole group with axes and swords and... well you get the picture.
I sent everyone back into the fortress again, with no military and only about 20 dwarves left I wasn't going to risk losing the entire fort so soon into the game. they hung around outside, waiting for me to lower the bridge, all the while making a mess of traders, and any immigrants that happened to get too close while sitting outside wondering how to get in.... After 2 years they left... and then... I lowered the bridge again, trying to reclaim bits and pieces from all the dead traders/caravans.
A minotaur (almost immediately) comes upon us, a giant bastard that takes down 7 regular dwarves in less than 2 minutes, chasing them down then spreading bits of them all over the battlefield before they even realised what they were running from.
I assemble the saddest looking squad I've ever seen, they'd been training less than a year, most if not all of them were recruits, some armed with iron/silver weaponry due to the goblin captures/corpses. they massacred the minotaur in about 10 minutes, one of the squadmembers got 2 or 3 good hits in, he ran for it, and he was faaaast. bleeding from just about everywhere, they cut him off at every turn and embedded his skull quite neatly into his brain, spreading most of his limbs across a 20 metre area while they were at it.
My question is this: how the hell did my previous squad, which was comprised of mostly proficient sword/axe and so on dwarves get completely owned by a ragtag bunch of goblins and yet a bunch of completely incompetent dwarves take down a minotaur without breaking a sweat? was it the weapons, just pure luck? or a mix of both?