I'll withhold final judgement until I see the feats and whatnot, but everything I see makes me think we will be replacing Zeitgeist's firearm rules with something else. These weapons are not tempting at all, they're a handicap.
I've linked to a thread with two of the feats mentioned in it.
You really don't think that three feats (Superior Weapon Prof, Firearms Expertise and Quickloader or equivalent) is not worth it for a ranged weapon that is range 20/40, prof +3 (a total of +4 with expertise), 1d10 damage, brutal 2, high crit, and reload free?
When compared to a longbow with Bow Expertise, you spend two extra feats for +1 prof, -1 per tier damage, brutal 2 and high crit. Seems like a fair swap to me, especially for rangers and other ranged multiattackers.
Or two feats (Firearms Expertise and Quickloader; one if you don't have much need for your minor action) to go from daggers (+3 prof/1d4 damage) or hand crossbows (+2 prof/1d6 damage) to pistols (+2 prof/1d6 damage, brutal 2 and high crit) for thieves and rogues?*
Firearms aren't terribly viable as weapons for prolonged use by non-specialists because the feat (or action) investment is too high, but that seems entirely appropriate to me. This isn't revolver-era technology. This is the magitech equivalent of flintlock. I've previously commented on the apparent oddness of having flintlock-era firearms in a setting that has cannons and steam-powered battleships of the like of the RNS Coaltongue, but if it's flintlock-era firearms you want, this system is IMO an excellent way of implementing them.
And the ability to have a pistol or carbine built into your melee weapon is a
massive step forward, as it avoids (at least for a turn) the weapon-swap dance that melee characters need to engage in if they're unlucky enough to get immobilised out of reach of an enemy.
*I'm assuming here that 'analagous' means for all intents and purposes (such as for Rogue Weapon Talent).