Also, syntax is superficial. Sure, some languages remain clunky and verbose even after getting to know them, but more often than not there's a reason why a language "looks" the way it does. Take J, for instance. It's a syntactical nightmare at first. But once you get used to the intricacies and discover the semantics, its code becomes oddly efficient and you wouldn't want it any other way.
[EDIT: Moreover, graphical representations of code aren't as desirable as you'd think they are. You can find plenty of attempts at turning UML (and similar stuff) into a proper programming language. It's about as cool and helpful as using Word when you could have emacs and LaTeX.]