My request is to simplify the “New CSS Rule“ dialog box (see picture below) into 1 selector field without radio choices or drop downs.

It Confuses, Rather than Helps, the Newbie
I believe the original intent of the CSS creation dialog box was to teach or inform the user that they have selector choices. The problem here is that it seems to confuse the newbie more than it helps. 

HTML Tag Selector Drop Down
Some may argue that this is a nice feature, and one reason to keep the radio button choices. However, this feature quickly loses its flavor  once the user is overwhelmed by the number of tags. Its much easier to simply write the tag in manually. I understand the argument for a WYSIWYG program where the user does not need to know HTML, however, this drop down still requires them to choose the appropriate tag.

I think the suggested selectors that Dreamweaver supplies is enough, and with the addition of the make “More Specific” and “Less Specific,” (Dw v10 CS4 Beta) there is no end to how this can help the novice. 

Gets in the Way of the Professional
Once someone knows how to create and manage CSS, there is no need for these training wheels. In fact, they get in the way of production. I do not know how many times that Dw has chosen the last default radio button and I wrote some advanced selector only to be told that classes must begin with a period, or some other warning. 

There is a Workaround
You can always keep the Advanced radio button selected and Dw will let you write any selector. This still requires that you check to ensure that radio button is selected when generating a new CSS. 

Suggested Fix
Perhaps, at the very least, these training wheels can be turned off in preferences (like an advanced editing settings choice or something similar). Personally I think that anyone venturing into creating CSS through this dialog box will only need a single field where they can type whatever they desire. A help button in the dialog box could take them to the help pages regarding CSS creation in Dw. 

As it stands, there will always be a learning curve regarding CSS implementation. And Dreamweaver is not responsible for teaching this through its features, but rather its help menus. I do realize this is a balancing act, since Dreamweaver is also meant to do it ALL for the designer. But the current option does not help, but hinders the user, even if it is a good intention.