Sketch assistants were a good idea, but I think the technology wasn’t available at the time to make them truly useful. They could basically list out areas of your design that had issues, but wouldn’t actually do anything about it for you.
Now that AI is out there it seems like the perfect thing to combine with assistants. I know I’ve seen Emanuel mention that they are really considering a good / ethical way of using AI. This seems like a good place to start to bring back assistants from the dead.