I like this direction, but I worry about developers involvement in the design of the DSL becoming the new bottleneck with the same problems. The code which becomes the guardrails cannot just be generated slop, it should be thoroughly designed and understood imo

Sure, that's why I think that it will mostly be SaaS businesses doing the DSLs, because the business contracts allow for more accountability than having employees do poor reviews, accumulating tech debt, that will only become visible down the road.