A slow query that shows up is the "latest" query, which specifies a size of 10,000 and uses scrolling without scanning.
Instead, add search_type => 'scan' and reduce the size to eg 1,000 instead of 10,000.
search_type => 'scan'
Also, no need to keep the scroll around for 1 hour - 1 min should be plenty
No one stepped forward to do this - Closing as part of Nov 2014 cleanup