If I was gunna rush to conclusions myself, it'd be that endurance and the strength for many many layers of armour is way more important than most of the skills. Iron in the raws is basically the same as Copper, while Steel cuts everything except Steel, so Silver maces and warhammers do more damage, more reliably, through steel armour, by virtue of having that weight.
Discipline is of course vital if you have morale turned on.
The only reason your axedorfs are getting anywhere, Bjiip, I suspect, is you're all missing the 2nd glove and 2nd boot, so those bits they can cut off, and then they have a disarmed dorf to fight! Who mostly passes out from the blood loss, gets his helm removed, and is instantly decapitated.
Spears won't work because they can't remove the lower arm or lower leg and get that advantage, and they seem to get dropped a bit more readily in fights, so that certainly puts them on the back foot. Against soft armour though, just bang dead, bang dead, bang dead. Steel spears rule against most non-dorfs.
Where the silver hammerdorfs do it full on, breaking bones through armour, stunning their foes, disarming by legitimate joint, tendon, and nerve injuries, and then often missing their weapon anyway, out-wrestle the more injured axemen and eventually tear the upper spine.
Most fully-armoured fights are won, well, post-fight. A 2nd wave after everyone falls down will tear apart large numbers of troops, a single axe can unhelm and behead 6-8 stunned foes before they wake, where the hammer dorf will slowly destroy the steel helm on one to crush it's skull, and then everyone else gets up and he's done. Iron helmed gobs are much easier for hammerdorfs to kill. Steel armoured dorfs against iron- or copper-armed sharp weapon foes just sort of win, they're mostly invulnerable, as long as they stay on their feet, thus Endurance. Work them pumps, boys.
Random findings, stuff like wooden shields are obviously great at blocking, but half of them are destroyed in any length of fight against steel weapons, so maybe metal shields after all? Everyone should train wrestling, because it's a very common thing for an injured dorf to do to defend themselves, and totally kills people. Having limbs cut off is bad for your dorfs, make sure your amour set is complete. Armour user doesn't seem to do much of anything compared to just having slightly better armour.
But mostly, yeah, get legend in something so they keep training and put their physical stats up to maximum, like Endurance and Willpower and Strength. Candy is probably good too, for cutting anyone wearing steel, not that you should be fighting steel users.