The problem right now is that aiming down the sights feels A LOT slower than aiming from the hip. While that's a normal thing for console shooters, Destiny in particular has an even wider gap of difference between the two aiming modes. So you might be comfortable hip firing in one sensitivity setting, but then all of a sudden you'll find that aiming down the sights (ADS) is too sluggish/unresponsive. So when you try increasing the sensitivity to get better ADS responsiveness, now your hip fire aiming becomes ridiculously twitchy. It would be better if they'd offer separate sensitivity settings between ADS and hip fire aiming. For example you should be able to mix and match sensitivity 6 hip fire aiming with sensitivity 7 aim down sight. It's something that I think every console shooter needs to do, rather than forcing players to memorize whatever hard-coded settings they use. And you're right, it also doesn't help that the acceleration and deadzone settings are all out of whack. It's no surprise that aim assist is necessary when we're constantly fighting with the controls.

Its possible, but harder when aiming at an "item" try it while aiming at a MOB/player. I had a hard time adjusting to controllers untill I started making use of the "auto aim". Your crosshair sticks in the target. What I also started doing is: if a target moves to the left or right not compensate by moving my crosshair but by actually strafing to the same direction which jeeps your crosshair glued on the target (like totally different from pc )