We have tested this before, about two years ago, I think -- with some of the core team and contributors involved. Because there are so many files already in the database, sometimes the search, if "narrowed down" would not always provide the key forum topics. During the search, tested with some Core team members verifying, even the use of exact words (phrases), in "quotation", sometimes did not include the key files.
It is true that many people may not do any search at all. However, when a person starts to provide "suggested applets or plugins or modules" more than likely they might have done some search.
I see the comments sometimes placed by Moderators, that such and such application is already available, or some preferred way of doing the procedure has already been proposed and preferred by CPG.
To minimize doing unwanted search, is there a way that the preferred mode of doing stuff are listed in each pertinent forum section and made a sticky? I can even help prepare this (including the main posts where the features was introduced), if needed -- when I see notes by Moderators suggesting preferred applications: plugins, modules, etc. Moderators may edit them to include latest version.