The completion suggester showed an incredibly promising effect on the zero results rate. But, we're not at present sure what effect it has on result relevance, or on the numerous other use cases which are inevitably supported by the things we push out.

In order to gather feedback, we should make the completion suggester a Beta Feature so that users can opt in to it and give us feedback on its strengths and weaknesses. Here's documentation on beta features: https://www.mediawiki.org/wiki/Beta_Features

Note that the completion suggester is primarily for readers of Wikipedia, and making it a beta feature will only get feedback from editors. However, editors use search too, and their feedback on any replacement to our search functionality would be invaluable.