It would be great if the user could choose whether to show a list ascending or descending. For example I made a list for newest members, it would be nice if my users could filter the other way around so that they could see the oldest users.

Here's an example of this: (non community builder)
www.summitpost.org/user_list.php?username=josh&order_type=DESC&orderby=last_active&page=1
If you hit the advanced link it shows some options for searching for a user which has ascending and descending.

I know technically I could make another list which is no problem for me, but I have many user lists which means if I made a reverse version for every list, it would be hard for the user to find the list that they wanted.

I think this would be a nice addition to Community Builder.