Maybe, if I could be certain that the MQM was not involved in the revenge killings in Karachi after Raza's murder. Unfortunately, the sudden peace, almost as sudden as the violence, after Gillani brokered the 'code of conduct' between the ANP and MQM, does imply that the MQM was controlling the killings, and possibly so was the ANP, but I do not know the ethnic breakdown of the dead.
Even so, the MQM would be to blame for starting the revenge killings, since they started with attacks on Pashtun in Karachi after the murder of Raza, and quite frankly, whatever the ANP-MQM differences, I do not think either would go to the extent of ordering hits on senior political leaders on the other side. The MQM overreacted, again, and IMO showed that it has not even now matured and gotten over its insecurities.
In essence they are telling the Taliban and other extremists, 'you want to damage Pakistan, kill one our leaders, because then we will go crazy and start revenge killings, shut down Karachi and inflict losses of billions upon Pakistan.'