To unpack my objections to removing the unconnected categories a little bit, there are several factors which go into my thinking:
First, the unconnected categories were created by connectors, for use by connectors, trying to make it easier to identify individuals who still need to be connected to the main tree. They're broken down geographically, because some people tend to work on connecting (or sourcing, or improving profiles in other ways) in on specific location, frequently because they have expertise and access to sources in that location that they don't have elsewhere.
As is the case with many categories, people who don't actually use those categories don't see any value in them. And, unfortunately, some people seem to have the attitude that anything they personally don't see any value in must be removed from WikiTree. (Take, for example, the links to Queen Victoria, the profile of the week, and the WikiTreer of the week. I've heard from any number of people who don't like them and think that they should be removed, and never mind all the other people who think they're fun and like seeing them. [Or the much smaller number of people who take the opportunity to test and improve all the links in the chain between their own profiles and the weekly profiles that come up. Personally, my hats are off to them for committing themselves to taking up such a huge and ever-changing task.])
So my plea to people who aren't connectors is: "If you don't use those categories, don't worry about them. Just ignore them. They're not hurting you, and other people need them."
Second, some people seem to take the presence of an unconnected category on a profile they manage as some kind of black mark against them. (Granted, many more people get upset about the presence of an unsourced category, but apparently, some people take it as some kind of insult.) I'm afraid I just don't understand the thinking behind that.
The reason I joined WikiTree in the first place was because I saw A.J.'s TED Talk, and the thought of being able to find and follow links between me and the rest of the world was tremendously exciting. The months that it took before I actually managed to make a connection between my branch and the main tree were intensely frustrating for me, and I very nearly gave up. If the unconnected categories had existed back then, and somebody had come along and put them on profiles I manage, I would have been thrilled. To me, those categories are a flag saying, "Hey everybody, come and help these people get connected to the main tree." I would have loved it if a bunch of people had come along and helped to get my branch connected. Once I finally did find a connection to the main tree, I was thrilled, and every time I find a new patch connecting my branch to the main tree, I still get a charge out of it. I can't understand why anybody would not want help connecting to the main tree. (Or at least, anybody on WikiTree. There are plenty of sites, not to mention software to run on their own computers, for people who want to keep their sandboxes all to themselves.)
Third, while Chris pointed to the unconnected lists (like the Unconnected profiles for Sussex list), which Aleš was kind enough to create at the request of the Connectors Project, those aren't exactly the same thing. The unconnected categories should be applied to unconnected profiles where the person was born, lived in, or died in that location. The unconnected lists record branches, rather than individual profiles, and the linking profile is whatever profile in that branch which was added to WikiTree first, so while the presence of an entry in that list means (or at least probably means) that somebody in that branch has a connection with that location, it doesn't usually mean that the linking profile has a connection with that location. For that reason, while I use Aleš's lists to populate the Let others know what locations you are working on page, when it comes to working through the profiles in a particular location where I have access to sources so I can try to connect a branch, I use the categories, because if a profile has an unconnected category for a particular location on it, then I know that person spent time in the location and might show up in the sources. (Unless somebody applied the category by mistake.)
Granted, sometimes I find that a profile is already connected, in which case I remove the category and move on. It can be tedious going through a whole branch and removing the categories from every profile once you connect it. So I am fully supportive of Chris' idea of automatically removing those categories from connected profiles. I'm just not keen on having the categories themselves taken away from me.