Interesting perspectives on a variety of languages, at first. Then when he says that XSLT is the best language I was thinking that we are very differently minded. So I suppose it makes sense that the Tailspin language is completely incomprehensible to me.
Eve is a really interesting language where you define global pattern matches, using datalog-style unification rather than XPath, and these "templates" can result in state changes. So for example you can trivially define global invariants over the entire state, kind of like defining a database integrity constraint but for your program's state.
As an aside, I'm recently feeling disillusioned with Haskell—after loving it since 2004—as any kind of ultimate or next-level general purpose language, precisely because of the lack of this dimension. Dealing with relational data in Haskell is quite tedious. Even writing multipass compilers in Haskell is not very pleasant.