warcry's duration doesn't actually seem to be a downside to me—it has a 30-second duration but also a 30-second cooldown that begins as soon as the skill is used, so you get 100% uptime on it. increasing the duration and cooldown would only make it clunkier, since it only affects enemies who are in range when the skill is used.
i do wish we had some indication of how "threat level" actually works in this game, though i suppose we can assume it's in the same place as PSO2, where your aggro is based on how much damage you've done? regardless, being able to use warcry pretty much all the time actually seems to help a lot with activating hunter arts avenger.
regarding the partisan, i enjoy it a lot but i do agree that it has a few issues. the comparison to sword is pertinent: sword has imo some of the best and most versatile PAs in the game. twisting zapper hits in the widest vertical and horizontal area of any PA, works fantastically as a gap-closer, and does maybe three or four times more damage than any PA or technique with a similar radius. spiral edge has a very quick animation and can be easily used to exploit small openings on single targets with hunter arts avenger, and calibur streak is optimised for maximum damage on downed enemies.
by comparison, partisan has three PAs each good for one purpose only, which is hitting things directly in front of you; and i think fatal tornado is especially buggy, with only one or two of the first four hits actually making contact with an enemy, no matter how close you are to it.
partisan does have some things going for it, though: thrusting javelin has decent damage and doesn't need to be charged, meaning you can use it for hunter arts avenger on the last hit of a multi-hit enemy attack. in addition, the class skill "assault charge avenger" allows you to get the maximum benefit out of a hunter arts avenger activation, if the opening is large enough.
i understand that the new volkraptor with its 60-second cooldown is meant to be something of a safeguard against the old pso2 playstyle, which revolved around volkraptor exclusively for its damage. and it succeeds in that—in ngs, you can straight up ignore volkraptor in your damage combos, because it's useless. at level 20, volkraptor's damage cap is about 323 damage, which doesn't seem to be affected by enemy defence or weakpoint multipliers. this means that every 60 seconds you can use a special skill to inflict an amount of damage equal to less than half a PA, or one normal attack. volkraptor is also still finicky to use on specific body parts, since in order to build up damage on the volkraptor projectile you need to hit the same part that it's stuck in. even worse, unlike very similar skills such as the weapon action grenade on rifle, there's no ui indicator showing when volkraptor comes off cooldown. you pretty much have to guess, which would make getting maximum benefit out of it quite hard if it offered any benefit at all.
increasing volkraptor's damage to significant levels would unfortunately require the rest of the weapon's damage to be lowered in order to balance around it, which i think would be undesirable for most players. if i were to suggest anything i'd say to either (1) increase its cooldown to something like 120 or 180 seconds (on par with other big abilities like fighter's overload) but also greatly increase its damage, turning it into a bursty skill to use on bosses, or (2) rework it to grant a non-damaging benefit, such as restoring a large amount of PP when it explodes, or transferring any damage done to other body parts to instead hit the body part targeted by volkraptor.