I agree that end-game human teams can be a major pain. That being said I may be able to help a bit by sharing a build & tactic that I’ve found works really well against mercs & noble forces.
(TLDR concerning swordmasters: slow them down with dogs, nets & spearwall, eliminate other enemies, surround SM with shieldwalled tanks and hack them to pieces with 2-handers from 2nd line. Swords don’t fare well against dedicated defensive bros if you play smart)
Three basic parts of the method: defensive play, ranged combat superiority & patience. “Zeroth rule” is a well-equipped and leveled team (reasonably high fatigue number obligatory), but you know that already.
The team: 6 front line “tanks” (heavy armor, shields, defensive perks), 3 rangers (War Bows & Longaxes, Bow Mastery, Crippling Strikes & Fearsome obligatory) 1 sergeant (Crossbow & Longaxe, Rally to keep everyone at Confident), 2 flankers (clad in heaviest armor, using Crossbows & 2-handers).
The tactic is quite simple: as soon as the battle starts you fall back to an advantageous position (preferably high ground, if you are heavily outnumbered go as far as the edge of the map to prevent encirclement) and stay there (shieldwall up to prevent losses from enemy fire), letting the enemy come to you and keeping them at distance (spearwall) while eliminating targets of priority with heavy volume of bolts & arrows. You only engage in melee when you’ve got numbers and morale (the sergeant keeps Confident up at all times) at your side.
First order of business: enemy rangers. With Bow Mastery (and hopefully high ground) you are guaranteed to outrange them. Thanks to your tactical retreat they most likely broke formation and are no longer hidden behind a tight wall of shields. As soon as those are dead your second line is safe and you can drop shieldwall on your tanks.
Next are 2-handers who are easy pickings without shields while posing considerable threat. Enemy standard bearer is a priority to start breaking morale. Crossbows come extra handy here, especially goblin Impalers (to further disrupt enemy formation). If you have some expendable dogs they are a great distraction, I’ve had one mutt dodge 6 blows in a row and taking 2 more before dying, which bought me enough time to nail 2 enemies.
Now you’re down to toughest nuts, enemy “tanks”. I like to keep my spearwall up and bash away those that get through while peppering them with missiles (remember to give your archers extra quivers). Keep some nets & javelins in your bags to add that extra “ye mother is a wench” to the mix. If they’re not escaping yet they’re bound to break soon (remember you have Fearsome on your rangers) at which point you can literally just let the dogs loose at them and break out the popco… I mean meat jerky.
There it is. Not foolproof of course (bolts to the head happen), but if you have enough armor to weather a rare blow and fatigue to keep the defenses up you’re going to be OK, mostly by virtue of enemy not being able to overwhelm you with numbers. Hope it helps!