And if a designer had a working product after the "architect" part, you'd see a lot more designer-only apps being built.
The fact is that a coder CAN get a working product up without the design-equivalent of "coding". They can lay out a UI just as well as an average professional designer (I would know), but the execution will certainly fall short of an average professional designer (I would know).
With that said, I'd always prefer to hire an excellent designer before building a UI, but I rarely will because I like to build more than I like perfect UIs.
The fact is that a coder CAN get a working product up without the design-equivalent of "coding". They can lay out a UI just as well as an average professional designer (I would know), but the execution will certainly fall short of an average professional designer (I would know).
With that said, I'd always prefer to hire an excellent designer before building a UI, but I rarely will because I like to build more than I like perfect UIs.