USE AT YOUR OWN RISK
With the press of a button turn Guild Wars 2 into a true action experience. It displays a centered crosshair (23 available in 1.0, with adjustable positions) and moving the mouse now turns your character and camera. When ever you cast a spell or action it will temporarily lock on and perform on whatever is underneath the crosshair. Left Click auto attacks, Right Click dodges & Mouse Scroll can be assigned to whatever you want. (all can be changed) Your movement and targeting will be as intuitive, fluid and accurate as an FPS Bringing up panels such as Inventory, Map, Hero, etc will toggle you out of combat mode and give you your cursor back.
Arenanet's stance on mod use (up to interpretation): http://www.reddit.com/r/Guildwars2/comments/10a0qk/official_response_clarifying_the_stance_on_mods/