Anyone who are fans of the Soldier Class Line, please choose your preferences.
Hear me out. Instead of a crit boost. Give them impale cuz they have a pokey stick 
I always thought of Halbs to be specialized lance users, similarly to swordmasters/berserkers
Sounds like the perfect name for a Lance+Axe class. The Lance crit+ class I usually call Spearmaster.
i hate crit boost on classes that enemies have access to but if swordmasters and zerkers have it it makes sense for halberdiers (and snipers but enemy snipers with crit boost are double annoying) to have it if theyre lancelocked
The way I see it, Halberdiers, Swordmasters, and Berserkers are each mono-weapon infantry specialists who have the crit boost as compensation for being completely beholden to the weapon triangle (this can apply to Snipers too, although it really depends on what you do with bows)
I also like the idea that each has different specializations regarding their stat spread:
Swordmasters are fast and reliable, with decent resistance
Berserkers are strong and fast, with decent HP
Halberdiers are reliable and strong, with decent defense
Impale, Luna and crit boost all work well for halberdiers. I might be wrong but I think I got impale confused for Luna but I’ll take a look into that when I get a chance.
I don’t like crit boost on Halberdiers because it doesn’t suit them thematically. They’re a specialist but they have a more defensive design, where Swordmaster and Berserker lean offensively. A crit boost is also not desirable if you’re going to spam them as enemies like Tellius, and if they’re the only non-armor lance infantry that’s more likely. (This is half the problem with crit boosted Snipers.) Proc skills run into the same issue.
I greatly prefer what Engage did, giving them follow-up manipulation that plays into their hoplite inspiration. If you want to give them something to stand out I’d sooner advocate for a more team-oriented trait like that.