As others stated before me, haulers are broken in an annoying way - the game exposes DPS as a value to keep track of, but the real meta requires you to cash in on the resources to progress faster, which requires haulers. This made me invest a lot of various resources into haulers but still kept me questioning myself if I shouldn't be going for DPS due to some yet unrevealed game mechanic. Very uncanny gameplay experience. No matter how much I poured into haulers, they still kept lagging behind miners. On top of that, haulers get stuck at the bottom and near the wagon for random ammounts of time, which makes the grind even longer.
There is also something animated at the bottom of the pit, when digging the Essence Chamber - I can't tell what it is, because it's behind the ground heaps and I can't uncover them all even with haulers+fully upgraded mage . Players will miss this content.