Additionally, most real-world applications fall into very predictable patterns which can be encapsulated by REST API's with hand-tweaked SQL access patterns for

Additionally, most real-world applications fall into very predictable patterns which can be encapsulated by REST API's with hand-tweaked SQL access patterns for speed. You don't generally need arbitrary query patterns from the client, and Rails/ActiveRecord already has tons of problems minimizing SQL calls. If you've built a decent backend API framework, making a new route should be quick, it's just access/auth boilerplate plus whatever retrieval is the most efficient.