In practice, however, the type system constrains the programmer in many ways that are unacceptable to Lisp programmers: data cannot be interpreted as programs, lists must be homogeneous, and functions are not easily redefned without recompiling other dependent functions.
a real language:
1. does not natively support tail call optimization
2. moves all functional programming capabilities into libraries... but would ideally have none of that fp bullshit at all
3. limits anonymous functions to one statement
4. makes using useless things like closures more difficult by having no way of disambiguating local name creation and rebinding existing names; unfortunately whiny fp fanboys wont shut up so this gets implemented anyway