Of course you are free to suggest anything you'd like. I was just trying to point out that it is not just the US City Directory records which are excluded when you narrow down to county level (and therefore it's not a mistake or error) and there's probably a reason for that. Perhaps because if all the national collections were included, it would be harder to find the more regional collections. The nation wide records are pretty easy to spot, especially the big collections like the US City Directories, so it is not as necessary to include them on a regional level. The whole purpose of being able to narrow it down regionally is to exclude all the well known, national level records so you can find the regional ones.
I've never felt the card catalog is not comprehensive and never had a problem finding or using the US Directories collection.