Officer in general has been weakened way the hell down. They nerfed the fuck out of it for a while, which needed to happen. The whole build one god and give it infinity turns shit was just stupid and balancing the harder difficulties around that made the game unplayable for normal people. But the new limit s on turn chaining and how high you can pump round one movement make having more than one around completely pointless and they give you Cassie (and two useless tits) with that setup already. And the game really punishes you for keeping your guys together, especially at higher difficulties. To me the main meta now is mostly Assassin for percentage based damage, as there are so many ways to quickly build Lethality and the direct damage abilities are abundant with that class. This is especially true at higher difficulties when trash enemies eventually start having more hp than the entire party. The game also starts making liberal use of complete damage immunity for turn one to gimp alpha striking, so having one agro tank becomes a must (either Abelard, who's only real edge is brace for impact or a custom who will be better if from a Forgeworld background) so you can wait out the plot armor timers while clearing trash. You move around so much that small tactical zones are kind of pointless, anyhow. The items you get at the time also massively impact your choices.
But core party pretty much always needs these key elements, imo:
Tanker w Taunt and Shield- (Abelard or a custom) Need this guy to deal with parking major enemies while the group mops up the trash, especially ones with extended "I am immune to everything plot armor" like the Genestealer boss and the named Necron Destroyers.
Sniper Psycher Buffer- (Idira can work here, but she sucks compared to any main) Start Santic then maybe add a little pyro later of you feel spicey. When you get the right gear, shift to the Richochette game plus damage all enemies when you buff trick. This character is critical for nailing distant annoyances quick and early, as well as attacks that deal damage based on enemy hp percentages making boss battles WAY less tedious. Give her the I go First watch and your group will enter every battle fully buffed out and most enemies dinged up and debuffed into childhood. By that I mean there is an item that does minor damage to every enemy combined with abilities that perma stacking debuffs and buffs that trigger each time you do damage. Start every turn by spamming all the santic buffs and anyting else psychic you may have. I think you guys can do the math from here.
Melee Pyro Specialist (Heinrix is ideal, but great for custom main, second class executioner or assasin)- Once you get the I am always burning shield and have the round one attacks equal psi rating items, this build just takes off. So much bullshit can be stacked on this builld to make it hit harder and it comes in two awesome variations: Assassin percentage damage specialist or Executioner Debuff burst damage god. Heinrich comes with most of the base kid right out of the gate, as the few Santic things he starts with synergize with everything else. Ridiculously hard to kill, deals tons of damage, and if you need to do damage at range you can swap to staff and burn everything to the ground.
More Dakka Person (Argentia is the hands down best, but Wulfgar can come close as will a custom)- This should really be called the Golden Bolter guy, because that is what makes this horse shit work. Basically the Golden Bolter gets added shot rate based on a stat bonus, AGI I think. So you can either slot the bolt casing and the heroic that gives you bonus shots based on fire rate and pump out over 70 auto hitting single shots a turn with even midgame abilities, or run around hosing down enemies with 14+ bullet bursts two to four times a turn. Mid game and early game, you can moonlight with a flamer/melta until you get the entire combo going. With an item and ability your reload goes down to zero AP and at that point the rest is academic. The reason Argentia is best at this (if not the most powerful party member in the game) is she comes with most of the required baseline components of the build right out of the gate at level 1 and she has a very strong AGI initially. And being Ecclesiarch means she can boost the Hero Meter to get the combo rolling. This is both the least essential build but also the most powerful, because it just does damage better than anything else.
Cassia- (no subsititue) Arrives at the start with an AE that debuffs trash that it does not outright kill. She also has some of the strongest debuffs and buffs in the game, along with the single most powerful warp damage attack. And better yet with one item her AE stops hurting allies and actually buffs them instead. And she has both Bring it Down and Finest Hour, which are extremely useful. Best of all, most of her gear needs are obtainable early and few in number. She doesn't even use Psy Rating based gear, so you don't have her competing with other group members for key goodies. Just give her a nav staff with Devestating, the Eye buffs my pals item, and whatever armor gives her the best dodging and you are ready to go. She may not do the big damage, but she covers all the utility needs and arguably becomes the best tank in the game with her insane dodge rating and resistance based talents. And best of all she is strong from the moment you get her to the moment the credits roll.
Now aside from taking over for Cassie, the main protagonist can hop into any of those spots. I find making a tanking skill monkey or the pyro assasin dancer to be the most fun, plus you get screwed over by Chapter 3 a lot less. But sniper buffer is very doable, too. The last spot I generally set aside for So the Quest Can Happen party member or for whatever I feel like doubling up on (Wulfgar on my current Dogmatic Hard run, with my main in the tank skill monkey role). If you want to amuse yourself with one of the last second companion options, by that point in the game you will be so powerful you may as well go for it. Except Uron. Never take Uron, ESPECIALLY if you have a lot of chain psycher use, because his abilities will blow up the party. And he sucks in general.
God damn I love this game.....