I mean, some of the oldest traditional enemies of the Dawi are Trolls, who were one of their first enemies, Orcs, who are bigger than them, Beastmen and Fimir, and then they also fight other enemies like elves, humans in all their many flavors (Chaos, Vampire, Undead, normal), and...well that's actually probably it. Really, outside of skaven and goblins, the Dawi don't fight many enemies in the same height-range. And even then, the advantages pikes (long spears) have include ridiculous range for a melee weapons. That is a boon to fighting anyone and everything besides those that are ridiculously (I'm thinking like 75%) smaller than you.
Something to keep in mind is that when you fight in actual warfare, it's not like it portrayed in movies. Total War has it surprisingly right, soldiers would keep in formations, poking and prodding each other, not engaging into a massive free-for-all where everyone is scattered across the battlefield, fighting duels in the dust and fire. Spear formations give soldiers a simple, easy to use weapon, that gives them range over most other weapons, and that's when it's just human vs human. A spear, pike, or halberd in the hands of a Dwarf might give them an extra two to five feet of range to hit an enemy. They would also likely have a sidearm, in the case for a Dwarf, likely an ax, for if they lose their weapon, or if it breaks, or they just decide to switch to it.
Don't underestimate the power of stick long enough to hit someone while keeping them from hitting you.