We'd all have key roles yes, but we may not abide by what the Sycophant wants. Cause if you really think about it all any our characters could say screw it and open the gates to the city.  Could be the captain getting tired of it, the mercenaries wanting more cash, priests claiming that the gods told them too, or the rouges just wanting to see how interesting it'd get. Because no matter how loyal or how much cash is passed along, everyone has a breaking point sooner or later. A clash of Money vs Religion vs Loyalty, its a mind screw.