Sorry, you are correct about the hawks, I must have got it mixed up with Baharroths ability.
Yes, runes of battle are not very reliable, but you still get smite and DtW and that CP.
If you chose a warlock you would have enough points to swap avengers for defender guardians, otherwise 8x stomies are cheaper, but you lose some firepower.
I'm not saying you should use the CD every turn, just in case it becomes important to keep them alive, such as if they are on an objective, they need to hold.
Yes, forwarning is great, but it's not a cheap stratagem, however half of it's power is just the mere threat of it.