sort, limit for PivotFacet stats

Solr 5.0 added stats to its pivot facet component, so that this query

facet=true&stats=true&stats.field={!tag=t1}income&facet.pivot={!stats=t1}tags&facet.prefix=university

returns stats for each facet with a tag that starts with "university". Very fast.
It returns these stats: min,max,count,missing,sum,sumOfSquares,mean,stddev

The issue is that it returns these stats for ALL facets matching the query criteria. No ability to limit or sort, e.g. to return the top 20 earning universities.

If this functionality can be added, then Solr could deliver on a more complete ability for analytics, rivaling more complex SQL aggregate queries.