Add to the search the ability to save a number of named searches. The number of searches would increase based on the Team membership level. 
This would be added functionality to increase the value of team membership to, in turn, increase team membership.

GB says little about search; I don't think it's his forte.

That said, I have wondered  why he doesn't put out a call for a tiger team of volunteer members to work on search enhancement as a separate project he can manage (and control).  There are definitely professional project management, database, web, and search experts on this site, some of whom would surely be happy to help.  Heck, let's get us some slaves CS graduate students to do the work.

I don't know enough about his setup -- separation of production and development, code check-in/test, for example -- to know whether something like that could be managed.  I also don't know if his code is structured or partitioned enough that search could be worked on without any side effects or exposure of sensitive things related to site management/security.