I could also get behind a total redesign of the skills based on how it is being used. Rather than Pistols, Automatics and Longarms, Why not Single Round (SS and SA), Automatic Fire (BF and FA), Sniping (aimed shots), etc.? It seems like firing a modded heavy pistol on full auto has less in common with taking pot shots with a holdout revolver, and more in common with opening up with even something as large as a light machine gun, in terms of the skills involved in doing it effectively and sccurately.
It just crossed my mind, so don't feel bad about tearing the idea apart if you don't like it.
Thought about this, but it would have to be by strict firing modes - SS/SA, BF, and FA. That's a lot clumsier, though, than the easier solution of shifting Battle Rifles into Longarms, making SnS shotgun only or at least more effective in shotguns (Perhaps 4S in anything up to light pistol, 6S north of there, shotguns exceptionally being 8S?), and put in more special shotgun rounds. That way, any weapon skill is viable for a combat focused character, with the following balancing elements:
Pistols - High concealability, lack rapid fire options, if some sort of rule accounting for precision is added these would be counted as precise. Firing Selection Change rules might need a note about turning Pistols into Machine Pistols if FA is added. Hypothetically, you could move Machine Pistols into here, but that might be making this group too powerful.
Automatics - General utility, but not fantastic at everything. Concealability is worse than pistols, range is worse than longarms, but wide variety of weapon options allow for the tools to solve many problems. Removal of Battle Rifles keeps this from being the weapon skill to solve all problems.
Longarms - Not much middle ground on range, as they're either long range weapons or shotguns. Addition of more specialized ammo for shotguns means that there's more reason to use those (After a wendigo? Iron slugs! After bugs? Insecticide-soaked flechettes! Need to Kill It With Fire? Dragonsbreath rounds!).
And thus, weapon skills become more balanced. Tossing Gunnery into the group wouldn't be a bad idea, though.