With those things already covered, and to make the pistolperk not purely a damage-class, i was thinking of something around the likes of naming the perk "Agent" or something more "intelligent" like that, instead of "Gunslinger". The perk could focus on pistols and something about intel, but i don't know what. Could also have these damage-amplifying markers spoken about earlier (that could also just be tossed onto burning enemies though, boosted by the Firebug perk...)
But so far i don't have much original progress what this pistol-based perk can bring which is purely new (well, i do have new ideas in terms of utilizing ZED-time, but that's only a new combat-style, not a new role)
Fresh thinking from timur, nice one mate.
The only role I found to be lacking would be along the lines of an Intel class.
This classes perk could be a means of telling what direction the ZEDs are coming from and keeping the team from being jumped. Off hand I could think of a couple of different ways to achieve this. Either a scalable minimap (lvl dependent) of a small area around you or a sort of 'heat/motion' vision (please don't hurt me to badly, these are just off the top of my head).
Although a good team would (or at least should) keep all avenues covered it might be good for when when team gets split or scattered, or for more interesting maps.
I posted that in the gunslinger thread but instead of having "magic vision" or "Brier Vision", hving a new tool (either slot 4 or 5) that does exactly that.
Dual wielding should be given to a class as a self defence weapon, not as their main weapon for damage.
This seems to be pointing toward a Scout class. Not like the TF2 Scout, who is more of a Marauder/mobile combatant (like the Zerker is in this game), but an actual light-weaponry, info-managing recon class (like the one in, say, Battlefield series). Pistols or SMG's would fit such a class (pistols in this case since SMG's seem to be Medic's territory), and as for abilities a sort of zed-sonar could be used to indicate visually or audibly the location of Zeds, or perhaps even where they are going to spawn from (since zed location isn't really that important when they're coming toward you anyway).