I've DM some Planescape games on 3.5, 4E and Pathfinder, all of them post Faction War.
In my campaigns things are settling down after war and Dabus are slowly walking away from their admin job, after factions are gone.
Reading 4E's Manual of the Planes and DMGII gave me impression that Sons of Mercy job as "city guards" isn't good enough.
For my next session I'm gonna start showing players that a new police force is raising on Sigil. Instead of Harmonium's red, they wear blue and are far more tolerant than hardheads. Sons of Mercy will stick with Prison, while "blues" will patrol streets... well, most of them.
I think maybe Mutual Trade Association could be behind this, creating a mercenary force in order to make their business safe.
What do you guys think? Is it a reasonable explanation?
My idea for the city guard post faction war, was that eventually you'd just have a bunch of militias covering different parts of the city. In some places it's the Sons of Mercy, in other places it's the Sodkillers or Harmonium remnants, in others it may be mercenary groups or neighbourhood gangs.