Regarding aiming updates, they have only made two in total, and both were required and necessary updates. They do not update the aiming or any core mechanic on a week-to-week basis. If you're interested in what each weekly patch covers, read Bravo's weekly update, as it includes the change log.
The first aiming update was a hotfix. From launch, the aiming in Halo 5 was actually very flawed -- the speed of moving your aim diagonally was incredibly slow compared to the speed of aiming in a horizontal or vertical direction. This was a broken mechanic from day 1, however thankfully they fixed this in a large patch a few weeks after the game launched.
The second and only other update that has been made to adjust the aiming mechanics of the game has been to address this "squirrely aiming" issues that the pro team had at longer ranges. This jitter was caused by the way Halo 5 interpreted the controller input into the aiming ingame. In previous Halo games, the controller "dead zone" has been a pre-programmed, preset value, built into the game. This dead zone nullifies a portion of your controller stick movement to prevent stick bias or unintended movement. Translated to the player, this means there is technically a slight delay between when you move your stick and when your player moves his aim, simply because this dead zone setting ignores the first portion of your stick movement. In previous games, this was a flat value, and the playing field was even and consistent controller to controller. Prior to this update, there was no dead zone programmed into Halo 5. To revert to pre-update aiming, simply reduce your dead zone to 0%. However, please note that your long-range aiming will be susceptible to jerky movements, unless you have excellent stick control.
Also, just want to point out: it's not really helpful at all if you just say "the aiming is messed up." Please provide specific critiques and information as to what you feel is wrong with it, otherwise your complaints will not be heard or acknowledged.