Actually, my popularity with the dwarves and elves got a little low early/mid game, but I didn't have much trouble getting them higher by the end of the game without Corvus' help. Once I turned down the first (undead) faction decision it helped boost everyone else, and since the imps and lizards were moderately high to start with, another couple political decisions and the imps brought up their first faction decision, which I turned down, etc.
