Does good design up front matter as much if an AI can refactor in a few hours something that would take a good developer a month? Refactoring is one of those tasks that's tedious, and too non-trivial for automation, but seems perfect for an AI. Especially if you already have all the tests.

Upgrades, API compatibility, and cross version communication are really important in some domains. A bad design can cause huge pain downstream when you need to make a change.