Tactics for playing as the Dwarves.

Yes, it's true that staying on the defensive with a Hirdu isn't advantageous and only works against Orcs, but that doesn't diminish their usefulness; you just need to try to group up during the battle, but strategically. Often, the focus is on a single unit, and Hirdu help with that.
And even if we're focusing on attack/damage, there aren't any particularly important reasons that would prevent us from leveling up Hirdu; if there are, please name them.