I have an idea to work around that issue thanks to the wider variety of sturdy metals in the ES universe. Gunblades and even Gunblugeons never took off in our world due to the limitations of steel, but in the ES world there are metals stronger than steel, which allow for even sturdier firearms. I doesn't even need to be Ebony; Dwarven or Orcish are strong enough metals to advance the design of the Boom Sticks to use heavier calibers and take more damage. And I can assure you: Hardiness and durability is what orcs are known for, and it reflects in their crafts. And besides that, we can always add Bayonets to the Boom Sticks and make them into spears if need be. Bayonets are still pretty popular today too.

Frankly, I find gunswords to be a very... Impractical idea. I wouldn't be surprise if a daedric artifact would take the image of one, but you'd need the power of the gods to make a bonefide gunblade that isn't just a dagger on a Boom Stick. Plus, it's easier to teach people to to hit something with a stick than to show them proper slashing and stabbing techniques with a gun blade. Malakaus isn't looking for exotic weapon supremacy here; he needs to make something the whole crew can pick up and use with as little training as he can get them to do. While "Point and shoot" is an oversimplification of gun usage, it's certainly easier to tell them to do that than to hand them a bow and arrows and expecting them to figure out how to notch and aim with a bow on the fly. 

A Boom Stick should be able to be given to a random peasant and make them capable of killing an armored warrior simply by telling them to point the barrel at the target and pulling the trigger. Additional the Boom Stick would give fighters a Medium Range option; against enemies that's too far away for melee but too close to attempt using a Bow without the opponent closing the distance. And since not everyone is magically capable, the Boom Stick can be used as the alternative for the magically inept.