If only attributes hadn't been capped. We could've trained up dwarves to insane degrees and then just have them fighting demons for the rest of their lives.
Oh, they'll be fighting demons for the rest of their lives alright. All three seconds of it.
On a brighter note, I think the following is appropriate inspiration:
"We do not know what our chances of survival are, so we fight as if they were zero. We do not know what we are facing, so we fight as if it was the dark gods themselves. No one will remember us now and we may never be buried beneath Titan, so we will build our own memorial here. The Chapter might lose us and the Imperium might never know we existed, but the Enemy — the Enemy will know. The Enemy will remember. We will hurt it so badly that it will never forget us until the stars burn out and the Emperor vanquishes it at the end of time. When Chaos is dying, its last thought will be of us. That is our memorial — carved into the heart of Chaos. We cannot lose, Grey Knights. We have already won."
I'm imagining tiers of siege weapons and crossbow emplacements around a central point manned by 160-odd dwarves, and a single lever to smash open a portal to hell.
Once I figure out how to work the military screen I'm going to try building a fortress dedicated entirely to defeating the underworld. All of it.
80% of the population would be military, supported by the finest armor and weapon smiths in the realm. Station them next to an adamantine tube, construct elaborate fortifications.
And then breach the tube.
All migrants instantly go to the military to bolster the front lines.
Legendary surgeons and doctors tending to the wounded, turning them around and sending them back to the front lines.
Huge catacombs with legendary engravings of dwarves fighting demons with masterwork coffins for the glorious dead.