What I'm really trying to say is that a commercial website will grow with time, and there does come a point as mentioned by someone earlier that the code will need to start being looked at. This should not be dismissed by the programs developers.
No. If you're developing a site in XWD the code doesn't need to be looked at. It's not designed to be looked at or altered. It's written on the fly each time you export the website.

The fact that 3rd party developers wants/can't rewrite the underlying code is the whole point regarding XWD. If you want a 3rd party to change/edit your site don't use XWD unless the SEO knows and uses XWD. (Now there's a market opportunity).