I get a lot of complaints from users that when they're in a tool and do a search, they do not get the results they want. Basically, I think the expected behavior (at least of our users) is that if you're in Phriction, a search will default to Phriction and can be expanded if necessary; similarly, if you're in Maniphest, a lot of people expect search to default to just covering Maniphest tasks. It's obviously just a minor feature, but an extra two clicks per search tends to add up when multiplied over hundreds of people.
If nothing else, it'd be nice to have a site-wide preference like "Scope searches to the current component by default".