Butcher 1 WoW a good idea?

Unless your caster is really good at protecting them I think 4 units of doom reavers is the absolute minimum. I'd drop Fenris or two outriders and then Bradigan or an escort for another unit.

I also agree on Ruin. 8" threat is nearly unplayable. I'd go with Ruin and maybe a marauder as the battle group and pick up more reavers.

And, even after that, if your meets is competitive you might have a better time with another style of list. There are better casters for WoW and better themes for Butcher1. If you're just looking for fun but functional, 100% go for it.