Okay, I noticed a major problem. If you change the list to show, say, the servers with the most players first, it will show you the list in that order, but that's it. It does not actually change the list for you... well, here's an example:
Let's say that when you first connect to the launcher, a CTF server is the first on the list, a Doom 2 coop second, and a Doom 1 coop third. You re-arrange the list so that it shows the servers with the most players first. Now the Doom 2 coop is first, the Doom 1 second, and the CTF third. If you join the first one on your list (D2 coop, as it appears), you will actually join the CTF server. While on your screen it looks like the server list has changed, it actually hasn't.