Wikidata uses array fields, it's likely that popular items gets more aliases, the all field is affected as well.
We know that array fields may cause troubles with length normalization causing popular items to have low score.
The plan would be to tune the BM25 b param for:
and proceed as follow:
1/ reindex relforge to setup different similarities for these field
2/ tune the b param (once the similarity is set we can close the index to tune it and iterate like that)
3/ submit a patch to wmf-config to add a wikidata profile in wgCirrusSearchSimilarityProfiles