I'm not sure I'll ever use these guys as they're kind of pricey (12 pts) for what you get. The Ld of 2 is pretty crippling. Also I can't remember if these guys were in a loose skirmish like formation in 7th edition but in 8th they rank up. These models are not going to rank up at all. It's just not possible.
I also finished up a Herald of Tzeentch on Disc.