Don’t know any game that really reflects the game-changing aspect of firearms, but I think that’s because game designers make a point not to, to keep melee combat enticing and armour relevant, especially in fantasy. In the first edition of 7th sea, firearms automatically cause drama wounds IIRC, so there’s that…
That's just…… a simply tradition of world style.
Most of these fantasy table game's worldscape are similar to the Earth of the Mideval or Renaissance, with the addition of magic and a lot of magical creatures as game changers————even so, the effects of these supernatural factors are so great that the spellcasters of the 3E era dominate everything, and warriors are just the henchmen of their mage masters. therefore those shity wizards of the coast had to greatly weaken the spellcasters in 4E and 5E.
But if we take it seriously, in a fantasy world filled with magic, supernatural creatures, gods and devil&demons, it is normal for various spellcasters to dominate everything of such world. warriors who can only rely on their muscles and mundane battle skill, even if they lucky enought to get a lot of magical equipment, they still cannot change their status as second-class citizens or even slaves.unless they are atleast some kind of spellcasters such as paladin,ranger or duskblade(magic swordsman)——————the 3E era, although lacks of game balance, but happens to be a version that reflects the reality of a fantasy world which full of magic power and supernatural beings.
and when the era of firearms coming, they are just another game changer besides magic. the spellcasters are clearly able to quickly perceive the value of guns and know how to fully utilize their advantage(and weakness). In a fantasy world, adding fully automatic firearms (rather than ancient matchlock guns) is just another game changer.
In fact, it hasn't changed manything but change the overall style of the world from the Mideval/renaissance to the modern era,and these mundane warrior class will become more balanced due to the widespread use of advanced firearms, and without the need to weaken the spellcasters.