In a brainstorming RPGnet thread on mixing D&D and, um, communism, brianm came up with an interesting scenario…
First, you make firearms as dangerous in the game as they are in real life. Bullets penetrate any mundane armours, so your AC is based only on dodge and magical bonuses. Second, give muskets exploding damage dice, meaning any roll of the maximum on damage gets you another roll, added to the first, until you stop rolling the max number. Finally, give a volley bonus, so that groups of musketeers are more dangerous than the same number of individuals.
Now you have a recipe for replacing those uppity heroes with common folk. You also have the makings of the birth of the modern nation-state.
To play epic-level heroes at this historical moments sound to me like a very awesome idea.