Longbow is one of the most versatile ranged weapons in the game, albeit it still has one bugged damage profile (charged bodyshot against berserker armour class deals less damage than uncharged bodyshot). It one-shots any special and SV by default with headshots and when kitted with one stack of skaven, chaos, armour and infantry damage, you can guarantee 2 shot bodyshots on all specials, stormvermin, 3 bodyshots maulers and as WS, over pretty much any distance. Put longbow on Shade, take ranged not breaking infiltrate and kill half a SV patrol without them even getting triggered. Longbow’s weakspots are boss damage, which is low, and CW, since even crit headshots don’t stagger them much to pin them down. WS can potentially kill CW with 4 headshots, but since headshot zone on CW is surprisingly small (in all honest, it should register a tad bit lower. With longbow, it becomes especially obvious that even though you clearly hit the face, it doesn’t register), it is usually not worth it chasing this break point, as Keri has plenty good melee options to take care of them, Shade roflstomps CW anyhow and WS can very safely use CDR on level 25 since longbow is so ammo efficient that the odd CW can be easily taken down with trueshot.
Volley cross does suffer from low ammo count, but has tremendous burst damage. Hitting the break points for killing SV in one volley is simple, especially with the +15% bonus power talent, and again, with ranged not breaking stealth talent on 25, you can mow down SV-patrols almost single-handedly without them getting triggered. If ammo is a problem, run scrounger on volley and bloodfletcher is pretty much the only sensible choice on level 15, anyhow. If you want to boost your boss killing to absolute roflmao levels, take Hunter trait on it. Boss comes, throw Shrapnel bomb, blast your first magazine into the boss (with stacked crits, chances are very high it will proc during the first mag), use concoction potion and infiltrate boss for maximum damage.
Hagbane is godly CC weapon with very good horde clear, can guarantee Packmaster kills in a single charged shot, can control patrols and with str pot and barrage, absolutely melts through bosses, lords and patrols. Run it on HM or Shade with +15 bonus power, extra monster damage and Shrapnel and any boss will melt in seconds.
Swift bow is about the only ranged weapon that falls into the category “fun, but ultimately a gimmick”. Its only true area of expertise is horde clearing, which it does very well when stacked to 1 shot fanatics with uncharged body and 2 shot marauders with uncharged body, but since the latest change to gunners and warpfire getting their stagger resistance upped, it has taken a very hefty blow. Armour damage is low on charged body shots and okay on headshots, but even crit headshots don’t stagger gunners and warpfire anymore, so you basically need your trueshot volley as WS. Boss damage is bad and it chews through ammo that it might as well be a WS only weapon. HM doesn’t need a horde clearing ranged weapon since horde clearing is trivial for her and Shade doesn’t get increased ammo supply and after one horde, your supply is usually almost spent - and refilling your 50 ammo stack via bloodfletcher is usually not worth the effort.
My only suggestion would be to give swift the ability to stagger gunners and warpfire on headshots and increase the boss damage. I don’t mind it being basically only useable and fun on WS, but hagbane fills basically the same role, has insane stagger and ALOT better boss damage.
My other suggestion would be to give Keri an Averlorn bow with Starfire shaft arrows so she has an equivalent to Kruber’s and Dorf’s handgun. Could even use the same ammo profile, give it a low rate of fire but make charged shots pierce super armour and set stuff on (BLUE!) fire.