Rails 2 scopes are literally the case for composeability...
I'd love to see a solution with tradeoffs made the other way:
* syntax and semantics 99% like underlying SQL
* support for 99% of underlying DB functionality
* traditional areas where ORMs add value:
* deserialization into convenient data structures
* casting, quoting and escaping on the way in and out
* using stored association metadata for concise joins in the query