Honestly... The whole "people don't die instantly" is where Halo 5 just confuses the fuck out of me. If someone gets the jump on me, I'm dead in around ~2 seconds or so. Since apparently most people in this game have aiming blessed by fucking god or something and missing is same as seeing a unicorn.
The aiming still feels so freaking off even after the patch and honestly, almost seems worse. People have ESP or something, cause apparently my radar doesn't work and they know my exact movements without even needing to see me even when I'm across the map.
The more I play, the more I'm starting to hate the game. Which is never how I felt playing the other Halo's. Hell, at this point, I feel Halo 4 was even more enjoyable then this shit.
I'm not sure why you are confused. In most "other shooters" the time to kill or "TTK" is much fast that in Halo's.
Let's just talk starting weapons for simplicity:
in COD, a perfect AR kill (kill with 100% accuracy and headshot modifier) averages at about .18s.
In Halo 5, your primary starting weapon, the pistol has a perfect kill time of 1.1s. That's over 6x more time to react.
Also keep in mind that a perfect kill is much harder to pull off in H5 because it requires you to follow your target for at least 6x longer than in other games. and usually that person isn't sitting still allowing you to land these shots. Many players accuracy is less than 50%. So it could easily take, on 10x longer to kill some one in Halo when compared to other modern shooters.
Could it be that your reaction time isn't as good as it was when you played previous Halo'o?
Now that you bring up your issues with radar, that your opponents don't seem to have, it appears to me, that your reaction time and hand-eye coordination might not be what it was when you last got into a Halo game, so games with Higher aim-assists and lower TTKs suit you more.
PS: the update didn't change your controlls at all. It just gave you the ability to tune the controls to your likings. You've got a serious case of placebo effect going on..