Mate
DW doesn’t add unnecessary code to your pages. It even has a tool to clean your HTML. If you don’t like DW there are many tools available. Even Firefox has a free html editor.
My personal experience – CSS pages (tableless sites) are SEO friendlier. Again that’s my personal experience because it theory spiders strip your html anyways.
Like people said earlier there’re must important things to focus when optimizing your page.
Good luck.