the tool/filter to rank users at certain levels of their IDs can be used inturn in this feature request - https://forum.inaturalist.org/t/create-searchable-expertise-and-interest-tags-for-identifiers-and-curators/67179/
those identifiers search can rank results automatically from this filter in-turn instead of manual profiles changes.
I also think if such a tool/filter is developed it is essential to take temporal factor into account - an Expert IDer for that taxon who never IDed that taxon in last one year (or inactive) is less likely to be interested in that taxon over another budding IDer who is actively IDing it in last months. so such component should goto scoring. Ultimately it is point of finding right user for person depending on that search without changing leaderboards per se as they are now.