Good question - django-simple-elasticsearch is definitely focused on generating a document from a single instance of a specific model. Of course, you can add supplementary data from associated models via M2M or FK models as you see fit (nested objects, etc.)

I've thought of adding in support for pushing bulk index request data to redis (for example) so that an Elasticsearch river could pull from it; this would decouple the app somewhat - but not completely as you've noted. It would likely help with throughput however, and still provide you with the ability to do pre-processing on the data as needed within your app's/project's context.

The Elasticsearch JDBC river isn't as flexible for processing data if I'm not mistaken, as it doesn't have context for the data? Please correct me if I'm wrong, but it's somewhat limited?