If I were to write a programming language

It would have several characteristics borrowed from everybody else:

• YACC-like grammar definition built-in; think of it as LISP macros but with custom syntax
• Closures
• Lightweight "processes" as in Erlang, Stackless, and Squeak
• Persistable processes as in Squeak
• Pattern-matching as in Prolog
• Primitives for parallel execution
• Variable argument lists as in Python (or perhaps C)

And several that would be new:

• All artifacts expressed as text in "code:" bugs, features, tasks, etc.
• IDE browsers based on examining artifacts in code
• Refactoring and versioning built into the language as primitives

I think I can have this language implemented by the time I'm 50....