There's another way to look at this. The more data you send per packet, the more that can be reasonably interpolated by the client in between updates. Diffs also becomes impossible of course in cases where you're using UDP. So for instance imagine you're only sending visible targets to a player in updates, and then there is a brief stutter - you end up risking having a target magically warp onto the player's screen, which is obv undesirable. Pack in everybody's location (or at least maybe within some as the crow flies radius) and the client experience will break less frequently. Of course like you said though, now the bandwidth goes up.