Give Runesmiths a rune with a hefty enemy slowing effect, or maybe a rune with an effect similar to the Light Wizards Net of Amyntok?
Since a lot of problems stem from the fact, that although somewhat equipped to fight cav and flyers, (Slayers!) the dwarfs just can't really pin down even the most reckless of enemy charges, as the enemy just ups and leaves. Dwarfs being slow, it would also be difficult for them to use said runes offensively.
Alternatively, if the above seems too powerful, a rune that makes them immune to being thrown around? This could also work on certain spells, bringing the Dwarfs more in line with their immovable, magic eating brethren of the TT.