I’ve had so, so many “builds”. I’m addicted to using them experimentally and concurrently, but I tend to get bored of each after a while of having a full band and a full inventory and spending ever more time on loot management and item assignation.
It almost embarrasses me to admit that I’ve NEVER had a single mercenary go all the way through the Perk Tree. I had one (from before the World Map re-working broke old saves) who was just a few points away from the final level up, but I never resumed it before the update. I guess this wasn’t a mean feat, since I played the game for aeons before I even discovered the existence of Level-Ups accompanying each perk.
Part of the reason for the above is that I’m very attracted to the idea of a gritty, low-power early medieval (Dark Age) world centred on shieldwalls and slaughterous melees, as opposed to a high medieval fantasy world featuring full plate armour and mystical beings.
My builds tend to be based, not only on Perk and Level-Up strategies, but also on imaginative “themes” based around particular weapons and/or items and/or environments. For example, one of my favourite bands is based around areas of woodland and awkward terrain, and never does work for noble houses, and features characters all named after figures from the Robin Hood legends, all of them dressed only in green/brown leather/cloth, and most of them armed with ranged weapons in addition to axes and/or spears and/or pikes and usually a shield (never a heater). I recruited a cocky minstrel and named him Alan a’Dale, and he has since become a captain and is also close to tier 2 on the defence tree. Robin Hood, Little John and Adam Bell are all weaponmasters who are also close to tier 2 on the defence tree. Robin Hood has high initiative and often uses two crossbows and a pike at the very start of a battle. Friar Tuck is (counter-intuitively) a nimble dodger, as is Maid Marion. Marion was originally a gambler with a massive, misshapen skull and a gnarly black beard, but she turned into a delicate red-head after a trip to the barber’s.
I also have builds centred around (e.g.): using bludgeons/maces and giving everyone Push the Advantage to start; using axes and giving everyone Crusher to start; trying (and mostly failing) to make throwing weapons effective; picking recruits, weapons, equipment, environments and perks in accordance with the idea of being a shadowy band of outcasts (i.e. thieves, gamblers, vagabonds, beggars, refugees, peddlers).
As a general rule, I like the Utility Tree the best, since it (a) allows you to use a greater variety of equipment and skills, so that battles are more interesting, and (b) over-compensates for most of the perks that you are sacrificing from the other trees. With Battle Forged from the Defence Tree you can get an extra 20% out of your armour, but with Brawny from the Utility Tree you can wear 100% as much without any more fatigue. Colossus from the Defence Tree is highly desirable, but the Utility Tree allows you to wear more armour, carry bigger shields and form more shieldwalls, so that you get hit less and lose fewer hit points when you do. Deflect from the Defence Tree makes it much less likely that you’ll be left without a shield, but with Bags&Belts + Quick Hands you can arm with a replacement in no time. Perks from the Offence Tree allow you to hit more often and/or do more damage, but with Bags&Belts + Quick Hands you can choose one weapon to smash shields, another to smash armour, and another to reliably rip through naked flesh. Pathfinder allows the band to take better terrain and trap the enemy on bad terrain, so that the hit chances are all skewed to your advantage.
In the earlier parts of the game, I usually take almost all recruits through the Utility Tree until one or two perks are gained from tier 2, but I mostly focus Level-Ups (where luck allows) on defensive stats, such as hit points and resolve and (if it was high basally) initiative. Then I start to add in Perks from the Defence Tree that fit with the theme of the band and/or with the traits of the individual. Colossus is always desired. Dodge is very handy if they had high basal initiative and have now regained (and/or are able to retain) a good amount of it thanks to Brawny and/or Weaponmaster. Shield Expert is a rather modest perk, but I sometimes add it in if the band is one that has lots of weaponmasters with heater shields.
In antediluvian game builds, I used to get one or two Inspiring Presences and then give all new recruits Hold Out as their first perk (i.e. starting at confident morale because of presence, and now getting +10 for all melee and ranged stats) – something that has not been possible since Hold Out was switched to tier 2. In the current game build, I don’t bother about tier 3 perks and, once I’ve got quite a few weaponmasters and one or two captains, I start to focus a higher number of recruits on the defence tree, and deliberately recruit thieves, gamblers etc. that will be good for this (i.e. Dodge, Colossus, Battle Forged, Nimble, Hold Out … not sure after that, but probably over to the Utility Tree to regain/retain stamina/initiative and morale).
For the Utility Tree, I like to: (a) compensate for not taking Colossus straightaway, by recruiting people (e.g. Farmhands, Lumberjacks, Wild Men) who have high basal hit points; (b) compensate for Hold Out now being a tier 2 defence perk, by recruiting people (e.g. Cultists, Gamblers, Squires) who have high basal resolve and who can become captains. Ideally they shouldn’t have a low basal max fatigue, or else they won’t be able to take full advantage of the tree.
For the Defence Tree, I like to recruit people who have high basal initiative and high basal defence skills, such as Thieves and Gamblers.
Messengers often have a decent bit of ranged defence to start with, and also have a high max fatigue that allows them to wear heavy armour, so that (whatever tree you take them down) they usually make good pikemen.
Although I rarely make use of the Offence Tree, one benefit from doing so would be that you’d do more damage and thus accumulate experience points (and perks) more rapidly.