I don't doubt that you could write a DSL that someone would be productive with. But then you'd need to keep a psychiatrist on staff to make sure the people using it don't go crazy. If we're talking about a full on, general purpose language, then you might as well start them on Thorazine ahead of time. Otherwise, you risk a programmer going postal.

In short, don't risk your or your coworkers' safety. Just say no to XML as a programming language.