I usually use the "Limit Display" action to search for packages. This is very nice, but it has one drawback: If matching packages are found across several deep subcategories, it's quite hard to navigate to all of the found packages. It's much better, when using the "Flat package List". However, this always involves creating a new View and re-entering the filter.
So what I would recommend is either
1) Have an option to startup with the flat package list. Or
2) Even better: Make it easy to transform the current categorized package list into a flat package list, keeping the "Limit Display" filter.