In the late 90s and early 00s I used Dylan for many things. (Algo syntax, scheme derived, CLOS) I think the biggest problem with Dylan is its rewriting rule based macro system. For a language as simple and powerful as Dylan to be saddled with a macro system that will give you sendmail flashbacks is simply wrong.
I think that perhaps what is needed is a new language that keeps the expressiveness and legibility of Dylan, but uses an equally legible syntax extension system.
So, I am writing one.