My broad thinking is that all syntax can be usefully flattened into "atoms" and "collections" (delimited & separated sequences of atoms and collectiosn), and then a language's syntax can be characterized by "what kinds of atoms are there" and "what kinds of collections are there". The structured editor that I'm building then works at the level of those atoms and collections (the 'reader' phase, in lisp), providing in my opinion a sweet spot of "just enough structure to be powerful & useful with out being overly restrictive & annoying".
Here's how I would describe various syntaxes:
Forth: