In a case like this, which is proactive, in a law enforcement sense, as opposed to reactive....a gang indictment vs. a murder, the DA is ready to go to trial, they have been ready since the indictment was filed.... it's likely his defense which wants to push the trial back, and continue to negotiate a plea bargain. In the federal system, a superseding indictment is fairly common in major gang/drug trafficking case, they round everyone up, on extensive, very serious charges, then they build on that, and usually supersede them, on more, and sometimes even more serious charges.