A good skin doesn't require VS, no. I have proven (IMHO) this a few times. However, to get the control over the content to the point that allows a truly robust skinning environment, you need to get dirty with how dnn is constructed (IE DNN designer skin editor or VB script to insert print style sheets). I'm am hobbled many times by the limitations of the presentation layer.
For instance, look at the automatically created, nested elements required to post a piece of text....
-Skipping skin elements-
#dnn_contentpane
- some type of container like a table or div -
#dnn_ctr###_Contentpane
#dnn_ctr###_ModuleContent
#dnn_ctr###_HtmlModule_lblContent .Normal
Content
Finding that content in the DOM is effectively futile as the IDs aren't known outside .net. Transversing from a known ID is problematic at best. You have to make your own IDs in the content and that is out of the question for a skin package.
Compared to Joomla:
-Skipping skin elements-
#container
#content
#main-content
.contentpaneopen
Content
The known structure means I can target the content with both CSS and JS. VS would allow me to target them but now I'm inside VS.
I could be wrong however and if anyone has a good, generic way to reach content via the DOM, please let me know.
As to the free repository, would it not make sense for DNN to champion it? www.dotnetnuke.com is where most people are going to start so why not? To date, there are zero free items in marketplace. To get free things you have to hunt through the forums. The core and modules are free of course.. However, they are controlled by corp (as they should be) which limits innovation.