That's exactly my point. The path to new game content can't be reduced to putting the blocks in the right place. You also have to come up with new mechanics out of thin air, consider the educational burden of your mechanics, the emotional tempo, how the level plays for different player types (speedsters, young players), how the mechanics reinforce the theme of the zone you're in, and more.

What I am pushing back against is the idea that since GPT can assemble blocks, that it's somehow approaching game design.