just because AI can find a working pattern doesn’t make it good

It's a wee bit more sophisticated than that, and will tend to find 2 + 2 even when 16/4 - 8/4 gives the same result. And if you suspect it's settled on an over-complicated solution you can add the prompt: "Search for simpler architectures which meet all requirements with less complexity." It won't always find the simplest possible, but generally speaking - I find LLM agents to be a bit better than my human colleagues in terms of finding good simple solutions and also finding problems within implementations.

None of us are perfect, and LLMs are trained on our writings. LLM agents within coding frameworks have progressed easily +10 years of human experience in their perfomance levels in the last 12 months. It's still an blueberries to tangerines comparison, a lot of what makes the LLM agents "good" is their speed and thereby ability to experiment with alternatives in a reasonable time.