Dreamweaver's output was clean in the demos as well. It didn't stop a veritable rats nest of code appearing on anything marginally complicated.

It's not an easy problem to solve without human intelligence.

It was also the developer's responsibility not to use DW in a way that would make it spit a mess of code. Just because you could embed a table inside a table of another table it mans you should.

With DW that was the only way to actualise certain designs though.