Yes, we do have one limitation and that is currently, we have set the name of the field to be tokenized.
Now the problem with this is that say we have a module with the name "Reference application module", then , elasticsearch stores it as 3 different words i.e. "Reference" , "Application" and "module" . Now suppose, the search query is "Reference" and we have other modules with similar names/ names with the search query in them like say "Metadata Reference module" . In such cases even though we'd like to see those modules with Reference as it's first word ranked higher, elasticsearch cannot distinguish between these 2 cases and sometimes ranks the 2nd module higher.This is because elastic search that both module names contain the search query without realizing the order. This is not a desired feature.
More details can be found here https://talk.openmrs.org/t/proposed-search-algorithm-for-add-on-index/11775/5