Because what if there where 6 equally important datastructures, or 100? The only datastructure you need to express when you are programming is the AST, in my hu

Because what if there where 6 equally important datastructures, or 100? The only datastructure you need to express when you are programming is the AST, in my humble opinion, and lists serve it well, visual trees might be interesting. The Lisp-2 design has a very good practical reason: 50% of a common type of mistake are impossible to make. More namespaces don't hurt a language, while less namespaces usually do (Javascript for instance).