As someone who often plays on two accounts at the same time, I'm usually coming up with new ways to make things easier when it comes to controlling two separate characters at once. When I'm outside, two player mounts make things infinitely easier, but when I'm in a dungeon, it gets a little more complicated. I have to switch between two characters to make them progress at roughly the same pace, which can get hard or just tedious.
My proposal is for KI to add a system where you can choose to follow another player if you are in a group with them. This means that if they walk in a circle, the wizard who is following will also walk in a circle just a few steps behind the leader without having to touch any controls. If the follower gets stuck behind an obstacle, they could automatically snap back to where they are supposed to be behind the leader. You could also choose to stop following at any time by pressing any of the directional arrow keys, much like getting off a two player mount, or the leader could make the follower stop following with some sort of interface button or leaving the group. Obviously this would not be a way to bring F2P players into members areas or anything silly like that, and porting away will automatically break the link between two players.