Currently the default operator for a query is OR. A global settings (not per query) should be available to specify default operator for all queries.
This is what I need to convert from Solr. Elasticsearch looks like a terrific alternative to Solr, but defaulting to a Google-style search of AND would even better.
That would be very nice for me too.
We've decided against this as we want to avoid setting explosion. This is easy to set in the application.