Apologies for not addressing your post directly, - I latched on to Tone's post about FormBuilder, as I have always had a bee in my bonnet about CSSFormBuilder being WebAssist's weakest link.
I can find nothing to disagree with in your post regarding the (formatting) code generated by DataAssist. I would go a little further in saying that the bloated code - with its maze of nested tags and classes - makes the page code a barrier, rather than an aid, to understanding the workings of the page and fitting the output to your site design. I don't see the need for it, but then I am fairly comfortable with CSS, where some may not be. Each implementation involves quite a bit of time stripping out the excess formatting and reapplying ones own preferred rules and cleaner design.
I would also like a version of DataAssist in which you can use the UI to edit the recordsets etc without it adding duplicate code and breaking the page, but I'm not sure if this is a problem with DataAssist or whether it is inherent in CS3/CS4.
I wouldn't use CSSFormBuilder (to build forms). The bloated code generated by the simplest of forms is massively disproportionate to its usefulness, something that was apparent from first use. As tone397472 says (above) it is so much simpler and quicker to add the required fields using Dreamweaver's Insert > Form menu, and applying one's own, more appropriate, styles.
I don't agree that CSSFB can produce attractive results - at least not without substantial deconstruction and re-styling afterwards, which totally defeats the point of using it. At the moment it would almost be easier to build a site around a CSSFB form than build a form to fit your site.
I would point out though, that WebAssist has acknowledged the degree of dissatisfaction that has been expressed (with CSS FormBuilder), and has indicated that a future release would be a leaner, cleaner version. I suggested here a few months ago that the CSSFB GUI should have a checkbox to tick to select 'no CSS/formatting', and I also submitted an example for a no-frills simple form option with minimal (but clean) css. I would like to see a similar 'no (or minimal) styling' checkbox in Data Assist, Security Assist etc. too.
Finally, the idea behind (and the potential of) CSSFormBuilder is really good. The process 'flow' i.e. - add an element, style the element, validate the element (with multiple options along the way) and saving as presets - all within a user-friendly UI - can make this an incredibly useful tool, as long as you don't have to spend frustrated hours afterwards making it look good or stripping out the excess. And once WebAssist have incorporated the facility to dynamically assign the elements to corresponding database fields as part of the 'flow', this will be a very complete solution indeed, and will remove the need to shop around for tools to fill the gaps and meet your needs. I would certainly expect to use it.