In so far as "unless you specify precisely how the user interaction should work, you will get bad design" that's true, but that takes you far from the vision of "give AI a prompt, it will provide you with usable output with minimal human intervention".

Claude is better because it validates its work visually and seems to have a more intuitive sense of what makes an interface pleasant to use.

Codex manages to be both rigidly literal about the spec but also prone to adding unnecessary explanatory text, helper elements and visual clutter, oddly like a 1990s ERP system.

The role of product manager/product design is literally to turn whatever is being asked for into the optimal solution someone would actually want to use - it's this translation instinct that is missing from AI.