Neither CMS Builder nor Site Sculptor require multiple licenses. The differentiation we make is between a solution and an extension. All of our Dreamweaver extensions have developer licenses, but require you to install an .mxp into dreamweaver and use dreamweaver in order to work. Solutions are pre-built applications that don't require Dreamweaver.
They do offer the same options once you have completed building a site, but the client experience isn't what we base the licensing terms on, it is the developer experience.
You would only need CMS builder if you were developing multiple CMS web sites and/or value the ability as a developer to view your data from within dreamweaver and design your cms content from within dreamweaver rather than using the online editor. Your end user experience should be identical.
