The aiming system in Halo Reach, just as in Halo 3 features Aim Acceleration which basically adds a noticeable amount of artificial positive and negative acceleration to your aiming, which in turn 'smooths out' your aiming. In other words, the amount of time it takes for your aim to speed up or slow down to a stop relative to your thumb movement is expanded over time.
This creates the sensation of sluggish aiming; the feeling as if you are skating on ice or under water. I am exaggerating with these examples, but those feelings do resemble what is present in both Halo Reach's and Halo 3's aiming system.
For those of you who would like a visual representation, here are some graphics to illustrate what I am referring to:
Smoothing vs no smoothing:
http://i.imgur.com/gYwvb.png
Smoothing:
http://i269.photobucket.com/albums/jj58/KurtiZ-NZ/EdhKb-2.png
No smoothing:
http://i.imgur.com/jilGU.png
Looking at those graphs, it may not look too bad because it is simply showing moving your joystick right to the edge and back. But imagine doing heaps of small adjustments (like you need to to keep your reticule on a moving target), and you can see the effect builds up.
Bungie's old games, Halo 1 and Halo 2, did not feature this interpolated acceleration to such a noticeable degree. Shadowrun and Call of Duty are the same way. Because of this, the aiming felt much more responsive in those games compared to Halo Reach and Halo 3.
Why would Bungie add this? It seems like it would only be a bad thing?
It makes aiming much more manageable for people who are new to video games. For those who are playing a FPS for the first time, aim acceleration/smoothing allows their aim to be smooth even though their actual input (thumb movements) are not so much.
The negative side effect is that for those who are more gamer-oriented and comfortable on a controller, it feels very awkward. It doesn't allow us to twitch our aim as we can in Halo 1, Halo 2, Shadowrun, and COD, and it feels very sluggish. Killzone 2 suffered from the same sensation, except to a much more extreme degree. Because it smooths out your thumb movements, it restricts you from flicking your aim on to an opponent, or from making tiny adjustments to where you are aiming because it gets smoothed out, and sometimes doesn't move at all depending on how small the joystick movement was.
Now, on to my proposition:
I understand why this level of aim smoothing is helpful to those who are new to gaming, so in order to make both those who are comfortable with a controller and those who are new to a controller comfortable, giving us the ability to disable aim acceleration/smoothing or adjust the amount with a slider, would satisfy everyone. PC games offer this option, as well as Unreal Tournament 3 when it came out on Xbox 360 and Playstation 3.
How awesome would it be if 343 implemented a controller setting under advanced options that is something along the lines of:
Controller settings Advanced Options
Aim Smoothing: Enabled / Disabled
or instead of just ON/OFF option, have the 1-10 option like with Sensitivity
It would not be difficult for 343 to implement this if we show them we would like it in Halo 4.
Some of you who play other games know exactly where I am coming from. Others may not. If you have not experienced what I am referring to, try playing Halo 1, Halo 2, Shadowrun, or Call of Duty MW1/MW2, followed by Halo 3 or Halo Reach. After doing so, you will probably be able to relate to this thread. If you still do not feel it, remember: I am not proposing to eliminate anything. Just the ability to change it depending on your preference.