Use of crosshair/cursor to improve targeting accuracy.

[Rongway]

Legacy makes it so that your character always faces forward and your character would back pedal instead of running towards the camera.

Other way around: legacy movement makes it so the direction you press is the direction you go on the screen, while the default movement setting make it so your movement will be based on which direction your character is facing. In Legacy, you will only backpedal if you move back while using the Strafe keys; for this reason, in legacy mode you should unbind "Strafe Left"/"Strafe Right" and use "Move Left"/"Move Right" instead.

In terms of a QE-WASD setup, the binds would look like this:
Move Forward : W
Move Back / Walk Backwards : S
Move Left / Turn Left : Q
Move Right / Turn Right : E
Strafe Left : Unbound
Strafe Right : Unbound
...
Move Camera to the Left : A
Move Camera to the Right : D

Then, despite the misleading naming of the keybinds, when you want to "turn", you move the camera with A/D and then move forward/backward with W/S. The Move/Turn binds will be for strafing.

(Tangential: the strafe keys should be mapped to Move Left / Move Right instead of Strafe Left / Strafe Right because the other major purpose of legacy mode is to be able to move at the same speed in all eight directions, instead of backpedaling. If you bind to Strafe instead of Move, you will backpedal if moving back and to the side simultanously. Binding to Move avoids this.)

Oh, so you're saying that people use mouse over on the list over to the left side and not actually on the characters on the screen?

In re: mouseovers, character models move a lot, and aren't great targets for mouseovers because they might move, or someone else might move on top of your intended target. You can avoid a lot of mistargeting by mousing over the stationary hud elements instead.