If you're firing a bolter, or casting a spell, your field of view MUST be restricted to first person. And for gods sakes no "lock on" targeting. Running around the game world, climbing and negotiating obstacles 3rd person view is fine. Melee combat should be done in 3rd person. However, if you're going to accurately put rounds down range with a ranged weapon, you should LOSE your situational awareness in the 3rd person view, and you should have to switch to first person view. Sure, you can "hip fire" from the 3rd person view at targets close in, but your accuracy should suffer significantly. If ranged weapons do NOT require a first person view, ranged classes or builds will have a huge, and unrealistic advantage over melee builds.