Actually here's another interesting bit: when berserkers rout an enemy unit, you'd expect them to chase after it as all others would, and that there'd be nothing you could do about it, or reign them in. But in my tests, after the berserkers have made unit 1 rout, they immediately charged to raise havoc in unit 2, paying no attenton to the routers anymore. Apparently they will not chase routers while in berserk, but go from unit to unit, routing everything in their way until they are dead. So their berserking, and lack of control, is not so much of a problem as one would think.