Just as you have folders in the workspace, why not have "tags" as they do on the left sidebar in the Mac finder window, or even tag combinations as you have when you combine keywords in a folder in FCPX?
Something like FCPXs "Smart Collection" would also be great.
In FCPX they are called "Keyword Collections", you can click on a keyword collection on the left side as if it were a folder, but it's not a folder. FCPX lets you combine keywords in folders, which would also be helpful in Kyno. This way you could have saved search criteria to search video by camera name, or resolution, etc.
It would just save time to click on an icon, instead of manually entering three different tags to do a search you perform on a daily basis.