We should explose sitelink count (and label count and statement count?) as a field in the search index for Wikidata (and any wikibase installs that use Cirrus)
then these can be considered when rescoring and ranking search results to give more useful search results.
this task involves implementing a hook handler for the CirrusSearchMappingConfig and CirrusSearchBuildDocumentParse.
at some future time, these fields could be exposed in a nicer way via the content objects and Cirrus be made to injest them more smartly. For now, the hooks are simple enough and most of the actual hook handler code would still be abstracted and then be easy to change later how it is connected to things.