Hurl Rock may be simpler and faster but it's 4 mana and more significantly, it's only range 0-1
while Flank Attack ( with Ring of Command ) is only 2 mana a pop - a huge difference, considering this way you can squeeze a FA + Orc Butcher ( With General's Signet Ring ) out of your 9 mana channeling.
FA is also range 0-2 meaning a Warlord taking a centre position covers 10 out of 12 zones.
The hidden bonus within Flank Attack is that it helps you trigger the Bloodwave Warlords Vet skill.
So, I was thinking along these lines :
I need something to draw the enemy towards me - a soldier who can apply the first hit
then I follow up with Flank Attacking Orc Butchers.
These guys can get scary fast : 4 dice + Vet + FA + Standard Bearer, that's 8 dice, Pierce +2 and 3 armour.
Here goes :
R1-19 : General's Signet Ring + Grimson Deadeye
R2-11 : Orc Butcher + Helm of Command ( Flank Attack )
R3- 9 : ready to rock and roll