Putting aside Cannith for a moment, one other thing to look at is how the LoBster's presence in Sharn will affect the city's major players. The King's Citadel & Dark Lanterns *will* find out he's there before long. They'll want to keep tabs on him and/or take him down - the Redcloaks and Blackened Book would prove helpful in that endeavour. But will they have enough leverage to do so? If the warforged in the Cogs are rallying to the LoB, or generally becoming more disgruntled, that shakes things up for Daask; they might be riled enough to send some enforcers after the LoB (or at least some of his troops). Anything that's bad for Daask is good for the Boromars, so they might use their influence on the Sharn Guard to give the LoB a wide berth to do as he pleases for a while, so long as he's kept to the lower wards. The Tyrants are a wild card, as usual. I can see Daask subtly encouraging and organizing anti-warforged sentiment, demonstrations, or outright mobs, with the Boromars trying to suppress/break them up, with a few riots as a result. What happens to industry in the city if the warforged in the Cogs strike or revolt?
There's also Cannith's tripartite factions to consider; Jorlana of Cannith West and Zorlan of Cannith East would both be pleased as punch to see Merrix and Cannith South roughed up a bit, especially if it allwoed them access to Merrix's Forgeholds.