This is what I keep coming back to. I'm sure I'm not the only one here who frequently writes the code, or at least a PoC, then writes the design doc based on it. Because the code is the most concise and precise way to specify what you really want. And writing it gives you more clarity on things you might not have thought about when writing it in a document. Unrolling that into pseudocode/English almost always gets convoluted for anything but very linear pieces of logic, and you're generally not going to get it right if you haven't already done a little exploratory coding beforehand.

So to me, even in an ideal world the dream of AI coding is backwards. It's more verbose, it's harder to conceptualize, it's less precise, and it's going to be more of a pain to get right even if it worked perfectly.

That's not to say it'll never work. But the interface has to change a lot. Instead of a UX where you have to think about and specify all the details up front, a useful assistant would be more conversational, analyze the existing codebase, clarify the change you're asking about, propose some options, ask which layer of the system, which design patterns to use, whether the level of coupling makes sense, what extensions of the functionality you're thinking about in the future, pros and cons of each approach, and also help point out conflicts or vague requirements, etc. But it seems like we've got quite a way to go before we get there.