What kind of initial damage are you thinking then?
I wasn't really thinking at that level of specificicity, but here are my quick thoughts:
3d5 damage is enough to kill a former a little under half the time (42%). This is a low enough chance that you can't use it and expect to not be burdened in the thick of combat, but the average damage of nine means that you should brutalise individual formers. With Bru2, this would now be true of Imps. Demons would still fuck you up, and anything tankier would require a melee specialist character to take on.
if it dealt less damage than that, it probably wouldn't be very useful without mechanics like bleed damage, or the ability to quickly ungrapple and weapon-switch (which would probably be overpowered given the double shotgun).
EDIT: I really like the idea of a new basic pistol too, but I'm not convinced it's feasible. I don't feel there are enough alternate mechanics to explore in the pistol family for a new basic pistol to not be either a treat to balance or just worse than existing pistols, unless anyone has any thoughts to the contrary.