There are definitely ways we can improve search functionality.
That being said,
Creating a "sorting by relevance" that would show titles first would be
A) redundant. You can already search titles only.
B) personal preference. Not everyone is searching for a title. Some are searching for the term in the description. If anything, perhaps another checkbox to search only in descriptions...but that is not a common method in searches.
Again, "relevance" in searches typically only refers to cases where the search will return partial matches once all exact matches are exhausted. This is not one of those scenarios.
"Quick Search" widgets in web design are designed to be fast, efficient, and simple. The more options are added to the quick search, the less "quick" it becomes. If, for example, I wanted to look at the Silver Expression Tool plugin but I didn't have it bookmarked, I would click "search" in the top menu bar which would bring up the quick search, I would then type
"expression tool"
with quotations, select the checkbox for "search titles only", and select "resources".
This brings up only two results, which was exactly what I was looking for:
Similarly, if I wanted to find the Timeline plugin I would search "Timeline", "Search Titles Only", and "Resources".
Now, what is interesting is that I did a similar search for
"Titty Magic"
, titles only, in resources. I did not realize you had named all of your plugins with no spaces, so there was no match. This search did return results though:
It appears that since the search did not find any titles matching "Titty Magic", it returned the next most relevant results, which are all resources with "Titty Magic" in the description.
So it would appear it does already provide relevance sorting if the "search titles only" box is checked. I might suggest that you include the name of your plugins, with spaces, somewhere in the description so that users who remember the name but don't remember that there are no spaces can still find your work. As they are now, they will only appear in results if the exact name without spaces is typed into the search.
As for what the quick search does in the results page, I'm sure that can be looked into. It does seem like strange behavior.
And as far as users not noticing/not being able to find the Advanced Search button, I'm not sure how it could be made more visible. But I do think it would be good to add some "search tips" to the quick search widget so that this can all be explained and there is less confusion over how to use the search.
Hope this helps!