last edited by Zias
It's definitely an option that's worth exploring.
Workshop does have a couple of advantages over City of Traitors, but I'll admit that it's unclear how valuable these advantages are in the present style of builds.
Perhaps the most important advantage of Workshop is the ability to cast lockpieces on consecutive turns while letting Bazaar do its thing. For example, you can cast Sphere on turn 1, then Sphere on turn 2, and play Bazaar. That gets both plans online immediately, whereas City of Traitors would require a second, suicidal land drop.
The other advantage of Workshop is that it stays around longer. Keeping the land count high on the battlefield can be important to leap over the deck's own taxing effects. Cards like Sphere and Loam get harder to cast in the longer games. So long as Workshop has an enabler like Urborg or Riftstone Portal, it can help support any part of the game plan.
All that being said, Workshops and City of Traitors aren't mutually-exclusive. It's possible that some number of each is a viable approach, or that the latter belongs in the sideboard.
As a final comment, although the deck features Stage/Depths, I generally don't try to "turbo" it out as is common with traditional dredge lists. I rarely keep hands that have Stage, Depths, and Tomb with no other gas--it's just too slow. Even in those cases where I have disruption and the Marit Lage triplet, I often prioritize the mana denial plan (Wastes/ Loams etc.) until I can make sure I can swing in without worrying about Swords, Repeal, etc. The real value of Stage/Depths, in my eyes, is that it increases the range of acceptable hands--you get to be more picky when you can win with the Dredge part, Marit Lage, or Hollow Ones, each of which have different enablers.