Originally Posted by boourns
I wish I saw an easy answer to this, but it seems like what people really want is some kind of view that follows their champion and also keeps the part of the action they're interested on screen as well. That's pretty hard to get right since we can't read your intentions.
I was reading this thread, and came across your message, and I realized I do have a solution to this that I have implemented before and it worked surprisingly well. It is very simple for an assisted mode, and while I would probably not use it since I like a free camera; it might actually be very good.
The idea is to use a center of mass approach. My implementation involved keeping things in frame around objects in 3d space, so the camera was controllable, but the focus of the camera followed the action. Basically, attach the camera to the target champion. Now locate all the other champions which are also on the screen (or a certain distance from target champion if it is easier), and find the "center of mass" of those champions (just average out their positions), and this is the new location you want the camera to look at. As champions come in and out of frame, the result will jump, so you really want to use a spring of some sort so the target point can be jumpy, but the camera will be smooth.