During my only run as a PC in this system I played your average dual pistol Mandalorian gunslinger, and found the dual wielding mechanic fair and pretty fun: just add another Difficulty (referred to as purple) die to the dice pool, and if you get two advantage, you can make the same difficulty check with your other weapon to essentially double your damage with the risk being that your first shot could do less damage, miss, and or not even allow you to take the second shot. I've since gotten myself stuck as the perma-DM for our games (I don't regret it) and had a recent thought to myself after talking to one of my PC's about how dual wielding works. How would the ruling work if a PC wanted to be a Besalisk, or Force forbid the six armed Harch, gunslinger? I don't think it'd be balanced for anything going against them if the gunslingers modified pool was still just the one purple with the two advantage being needed for the next shot, but if I were to add a purple for every extra weapon then at some point the gunslinger is going to hit everything save for his target.
Another related question I'm curious on: Would you consider having multiple weapons on a vehicle (not already linked weapons, like an X-wing's laser cannons) as dual wielding if they wished to shoot, say, lasers and proton torpedoes at the same time? And if so, and if they had about 5 different weapon emplacements, would the same rules apply from Dexter Jettster the gunslinger?