Korgan
Arbiter
The whole "Secret agency vs the invasion of whatever" angle isn't done enough in gaming. It should be about humans, though, otherwise the atmosphere is lost (see UFO: ET).
Actually, DoW 2 could've at least done something X-Com like. I don't like Nids, but they would've made good opponents in a turn-based Deathwatch game. You fight in special missions, assist the Guard in randomly generated battles and earn prestige, exchanging it for the favor of the AdMech, who build stuff and research the enemy, the Ordo Xenos, who assign specialists from other chapters to you, coordinate allies and call down Exterminatus when needed, or a radical Inquisitor for various shady stuff and dangerous relics.
OK, this sounds nothing like DoW 2.
Actually, DoW 2 could've at least done something X-Com like. I don't like Nids, but they would've made good opponents in a turn-based Deathwatch game. You fight in special missions, assist the Guard in randomly generated battles and earn prestige, exchanging it for the favor of the AdMech, who build stuff and research the enemy, the Ordo Xenos, who assign specialists from other chapters to you, coordinate allies and call down Exterminatus when needed, or a radical Inquisitor for various shady stuff and dangerous relics.
OK, this sounds nothing like DoW 2.