I also look forward to improvements and changes. But at this time I completely agree that the search engine algo needs a lot of work and it is much worse then before.
When searching for “contact form”, Contact Form 7 should not show up in the middle of the 2nd page. Perhaps you could put it back to the way it was until you can release the new ElasticSearch engine? I have been a WP user for years and its annoying to have to look through pages of results to find the plugin I want.
Regarding the algo logic, here is the weighting order that I would recommend: titles (20%), tags (20%), active installs (15%), ratings (15%), last updated time (15%), compatibility broken / works box (10%), keyword density in desc (5%).
Another idea for the algo is if you could keep a count per plugin of the top 10 most frequently used keyword search terms that lead to plugins installs ( while keeping in mind the uninstall ratio ). Then the results would be based upon actual users searches instead of the plugin authors tags, desc, etc. or even a complex algo on your end.