"Supports XML, YAML, JSON and SQL formats" - from the front page of http://www.liquibase.org/. What more do you want ?

As if programming in YAML or JSON is any better. And programming in platform-specific SQL, for all non-trivial purposes, ties you to the specific flavor of DBMS.

What I want is a DSL that is a platform-agnostic DSL: terse, typechecked, possibly "compiled" to some IR, with basics of semantic analysis, with support for (or at least awareness of) the quirks of the specific underlying platform.

Which in this case, depending upon your editor, can mean autocomplete and validate as you type. In spite of liquibase's newer YAML and JSON support, XML works very well here.