My balance does also not fit the real situation in any land in any time, but is much more interesting than Native.
I have made several lands really OP in terms of Native vanilla balance, but balanced against each other if rightly used - Rhodoks, Swadia, Nords. Others have got some boost, but they are considered as possible colonies for other lands to have wars for.
Rhodoks can train good Sharpshooters (like Sharpshooters they have by default) or Siegers, who have a very powerful crossbow, that takes 20 seconds to reload, but can one-shot many troops from very good range. They also have Pikemen (Sergeants with 1h Cleaver and a Pike instead of normal hand-items, Pike is taken from cRPG, as in there, Native pike is named Long Spear) and Shielders (the only units with shield skill more than 2, only Heavy Board Shield and 1hCleaver or Military pick). Pikemen are very vulnerable to ranged and are useless on sieges, but are well-defended against direct cavalry charge, Shielders are very vulnerable to cavalry charges, but well-protected from ranged and used to cover teammates from arrows. They are all, though, very slow, and, therefore, easily flanked in the open field, they don't have good armor or melee skills, so they are easilly pushed by well-armed infantry with shields, if it is ready for some losses from crossbows.
They also have Scouts - light cavalry with 1h swords and shields on coursers, useful in reconaissance, in chasing falling back opponent, but useless in direct charge. Best used in slicing enemy ranged units. I now think to give them some throwing weapon, as they are really useless, infantry is doing slicing ranged much better.
Swadians have everyone mounted on at least saddle horses, it helps them to easily move army on the battlefield. They are also well-armored (even crossbowmen), faster than Rhodocks on foot, and have perfect knights - both cavalry and infantry. Knights have fullplate, plate boots, gauntlets, Heavy Bastard Sword, Great Helmet (with stats of Great Winged helmet), Plated Charger from cRPG, Great Lance, Knightly Heater Shield, Spiked Mace. They can crush any defence in the flat battlefield, as they can outflank most armies, even Pikemen.
Sergeants are like knights, they have good athletics and Morningstar instead of lance and Steel shield instead of wooden.
Crossbowmen are faster and better protected, but lack reach, skill and power of Rhodoks.
Swadia is the most expensive faction, a big army of knights may make their owner lose a monthly city earnings.
Nords are not as universal now as before, they have many troops, each of them doing only one job good. Their troops are all mounted on the map, but noone of them is mounted in battle. They have two types of infantry - heavy (Huscarls) and light (Berserkers). Huscarls were a little bit nerfed, a little bit boosted - they don't charge as fast as before now, but they always have Spiked Battle axes and Huscarl Round Shields. They also have a stack of throwing weapons and a warspear to fight against cavalry. The are very good on sieges, as they are well skilled and armored, and they can destroy wooden shields easilly. Light infantry is represented by berserkers, they only have Great Axe and go naked. They have highest athletics, Power Strike and Iron Flesh skill. They can easilly chop almost anyone with their axes, but are extremely vulnerable to ranged attacks, especially bows with their good DPS.
Ranged units are throwers (Have a sword or axe, Heavy Round Shield and a special stack of 12 Heavy Throwing Axes) with good throwing skill and very good but short DPS, ready to disshield incoming enemy, and archers with longbows, a little bit buffed in damage but nerfed in accuracy.
So, the stratagy is very easy.
Rhodoks - make enemy charge your castles and have huge losses from crossbows, putting pikemen on flanks and shielders in front of crossbowmen in the field. Any fight with enemy cavalry results in huge losses.
Swadia - make enemy fight in the open field, or prepare to experience losses.
Nords - make enemy come close enough to lose his power of ranged (pwned by Axe Throwers) and cavalry (not enought distance to charge).