MostlyHarmless42
Adventurer
Does that not already happen, with firearms being in the DMG, mentioned in the Artificer class, and the Gunslinger (Matt Mercer's subclass)?
If none of that has effected your games, and you're willing to get rid of something someone else finds fun just to get rid of 10 minutes of explaining your world to players, I guess that just seems a bit selfish to me.
This again gets back to the core problem I have with the feat in the first place: any setting involving firearms is by design going to require a conversation with the DM in the first place. It granting proficiency as part of the feat is basically just wasted ink because any DM who wants guns will likely grant said proficiencies or allow characters to train in them without feat investments, and any DM who doesn't want them will just outright ban the feat screaming "NOOO!!!" from the rafters. I don't actually begrudge the feat for granting the proficiency, but I want it treated as a thing that isn't a balancing factor of the feat itself, which I get sounds a bit odd in concept.
And again, I get why something like the crossbow expert feat granting a bonus action attack is way too powerful for the DMG firearms, but that's really the problem: I don't like the DMG firearm rules. Without wanting to hijack the thread by getting into the whole typical "how strong are guns compared to a longbow, crossbow, or taking a sword in the chest?" debate, I am firmly in the camp that thinks that flintlock weaponry should NOT be stronger than the PHB weapons. As such the DMG rules in effect forcing the gunner feat to be "boring, yet functional" is ...frustrating to me. I do want the feat to exist and thus do not begrudge it, but I kind of wish they would differentiate firearms from crossbows and bows not by eliminating the loading feature, but somehow do some other mechanics, like failure chances, being too loud (maybe letting the feat grant the ability to silence them slightly? or repair them quicker if they jam, etc.).
I myself as a DM will still likely just either:
a) Treat guns like magic items in rarity and ban the feat except for maybe artificers/gunslingers (I use it as a rogue, not a fighter subclass),
b) Let the player reskin crossbows as firearms and thus not really need the feat to exist, or
c) Homebrew some sort of firearm rules if the setting itself is commonplace enough for them to exist, and then just treat pistols/"weaker" guns as simple weapons and stronger rifles/firearms as martial weapons. If their class has proficiency they have it.