The lack of anything like a pointer or reference type is more significant. That and pointers to code would go a LONG way to adding useful expressive power to the language. As things stand right now, there's really no way at all to abstract control flow, which makes a number of useful programming styles very difficult to implement, if not impossible.

For reference, the Microsoft BASIC 7.0 implementation contained about the only implementation of a GUI (text mode) framework that did not use pointers to functions. The result was something that worked, but had immense amounts of repeated complexity and boilerplate code.