There are already search parameters.
Ex: Add ar=10, bpm=200, *length>500 or length<500 (in seconds)* etc. to your search term.
If those above are too confusing, you can try what I mention below.
You can already type in the name of the difficulty you want in the search box.
Ex: Hard, Insane, Extra
If you want more parameters you can click the arrow boxes at the top right of the screen. There is a "Group" and a "Sort" selection box.
Ex: You recently got a map, but you don't want it anymore. Apparently you forgot the name. On the top right next to "Group" choose "By Date Added" in the arrow box. You can now see the map you recently added.
Heck, you can even add a beatmap to a custom group.
Ex: Right click the beatmap, click "Manage Collections," and create a new collection with a name of your choice. You can then view your collection by going to the selection box next to "Group" on the top right, then click "Collections".
I don't see any reason why we need more parameters than the ones we already have.
EDIT: You can also add "4k" in your search term to find 4k maps, "5k" for 5k, etc.