I'm going to contribute just for the sake of sounding smart...
The targeting and aiming systems for MechWarrior: Online are all based on the Mech cockpit's perspective. Since the third-person view mode is observed from a floating drone, yet the targeting systems are based on the cockpit, it causes a slight desychronization owing to the two different "viewing" perspectives - your Mech always views things from the cockpit, regardless of where you, as the player, are viewing things. This phenomenon is intended to occur because it prevents players from locking onto targets that are only viewable from the third-person drone, and not visible from the Mech's cockpit.
The consequence is that the targeting reticule will always be displayed where the Mech is aiming, and not simply "in the middle of the screen" like many video games do when changing from one viewing perspective to another. If this were a typical run-and-gun shooter with the option to change viewing modes, then the reticule would probably always be in the center of the screen, but MW:O has a robust target tracking and targeting system that depends on Line of Sight... This means that leaving the reticule in the middle of the screen like a typical shooter would allow players to lock onto targets that are only viewable by the third-person drone. The developers of MW:O, rather, made the aiming system 100% linked to the Mech's own viewpoint, and so when you sweep the reticle across terrain it will seem to jump around as it adjusts for range/distance.
You'll notice that these "jumps" almost always take place when sweeping your targeting reticule across environmental features and other battlefield objects that differ in their distance to your Mech. If you're in 3rd person mode and pointing out into the distance while there's a Mech in front of you, then you can move your reticule just a little to the side while trying to aim at a different point in the distance but you are actually making your Mech point at the object in front of you... Even though (according to the position of the center of your screen) it looks like you should be pointing into the distance. That's because the thing in front of your Mech is blocking your Mech from aiming at that position in the distance that you're trying to aim at with the drone.
Think of it this way: When in 3PV, you are not "aiming" left, right, up, and down... You're "ordering your Mech to aim" left, right, up, and down, like operating a remote-controlled car. The Mech will give you feedback about where it is aiming by showing you the reticule. The reticule will move around to where ever the Mech is actually aiming, and not where you "intend" for it to be aiming.
Edited by Prosperity Park, 08 November 2013 - 09:08 AM.