I had a question from my client recently asking if they were doing anything wrong while searching, because they couldn't often get good results for the document they were looking for.
I gave it a try and see the same results. Now that the client has entered hundreds of documents, finding the right one is getting increasingly frustrating. This is both when searching for a document in a link field (or for a rich text link), or just searching for a document among the list of documents in order to choose one to edit.
It's as if the search routine doesn't pay special attention to the title field, or doesn't even take it into account. When searching for the term "platform" I fully expect the one and only document whose title is exactly "Platform" to come up first or at least in the first few results. In fact it's showing up 14th in the results.
IMO the title field should be heavily weighted.