The Ability to Search YOUR family tree
Right now, there is no functionality to search only people attached to my family tree. If I try and find a person, it brings up results from the entire database...but I only want to see the record for the person that is relevant to me (a person I've added to MY family tree).
So my suggestion is to make allow an individual to search for a person by name only within their family tree.
If you're looking for someone you added (or contributed to in any way), use My Contributions. If you're looking only for direct ancestors, use the Fan Chart and your browser's Find function.
Otherwise, this is probably The Most Frequently Requested Feature on FamilySearch, but the one that misunderstands the underlying structure the most thoroughly. What it boils down to is scope: how should the Find function go about determining who is part of "your" tree and who isn't? Should it do this before each search, essentially doing a tree download every single time? Those can take several hours each. Or should it try to do it after the search, running the "View Relationship" function on every search result? Those can take half a minute each, meaning each results page would take five or ten minutes to load.2
I can see how that would be useful.0