I think some more pistol variety would be nice, but I don't think guns need to be buffed. (Well, to be exact, I want guns buffed and SoG nerfed, so that guns could have a use in other builds)
Anyway, I'd rather put new "alternative basic pistols" than new exotics/uniques, which are usually more powerful.
Basically, fire time quickly becomes negligible, so a 'quick fire' pistol could be good for the couple of first levels in the game... and useless after that. Unless you start with it, it doesn't seem worth to create such an item, I guess.
Most relevant parameters seem to be magazine size and precision. SoG makes most of the damages, but reaching 12 or more makes a difference, since it enables knockback.
What could we do with this ?
Here are some basic guns variants ideas :
Basic gun (just for comparison) :
1.0s firing time
1.2s reload time
2d4 damages (avg 5)
+4 precision
6 bullets magazine
Alt. fire : aimed shot (+3 precision, firing time doubled)
Alt. reload : dual reload
Precision gun :
1.2s firing time
1.2s reload time
3d2 damages (avg 4.5)
+7 precision
4 bullets magazine
Alt. fire : aimed shot (+7 precision, doubles firing time)
Alt. reload : none (or dual reload, if you want, but such a command shouldn't be on the weapon. It should belong to the interface. And anyway, it's quite useless)
The idea is just to have a gun with built-in EE, making shots more reliable. Weaker, and even worse than basic gun in terms of reloads, but better precision, which should also increases ammo efficiency. Since I think it might be quite weak, I buffed alt-fire (not sure it does a difference, but the goal is to improve out-of sight shooting accuracy)
Mammoth gun :
1s firing time
0.8s reload time
6d2 damages
+2 precision
2 bullets magazine
Alt fire : dual shot (-3 precision, fire both bullets at once, doubles firing time)
Alt. reload : same as previous.
Basically, this one is intended to give a chance of knockback to non MSS builds.
Glock 42 :
(9 or 12 bullets magazine, burst of 3 bullets, terrible precision) -> Either awful damages or overpowered ones (witg SoG). Too powerful with MSS or too weak with anythinf else -> bad idea (IMO)
Btw, I'm afraid those suggestions are not balanced, but I don't really see better ideas to improve pistols variety without reworking all guns & SoG itself.