Yeah, in DK2 you would have an assortment of item plans available to you. Then you could pop down a blueprint, pay the initial fee then and there, and then wait for some snot-picking troll to stop harassing the walls and move his scabby thong-clad butt over to the workshop to start hammering on things, at which point the item is produced and shuffled off to where you ordered it.
DK1, all worker-types would constantly be in the workshop working away, like researchers in a library (that's another thing, ALL minions could research in DK1, but some were just vastly better or worse than others), until the workshop's storage space was filled up. The items they'd create would be somewhat random, with more lower-tier items produced than higher-tier. Then you'd get a stocks screen with the available items, where you could then order one to be placed and it'd be up in just the time it took for an imp to drag it from the workshop to where it needed to be.
It kept workers busy, actually USED the workshop space which was almost entirely moot in DK2, and provided an actual sense of production. Sure, you couldn't get stuff on-demand, but it also meant that a larger workshop with more workers would provide you a larger selection and stock of items, instead of just fulfilling effectively the same purpose as a 3x3 with one really skilled troll, as DK2 turned into.