I wish they did this and had a better search interface. Their current "all in one bar + suggest" functionality works somewhat poorly for me.

Also I feel like they could reduce the needs for super great API docs if they had something like a query optimizer so that I don't have to care about the exact way that ES translates my queries into Lucene queries. My favorite bit is how if you permute your filters and queries in the wrong order you end up completely killing your performance (filter then query or query then filter).