I switched on Aim Assist for a couple of games of Turf Takeover and experienced the perfect example of how Aim Assist is problematic.
I was on the Zombie team playing Space Cadet and defending on Weirding Woods; Aim Assist was set to "Light"
I encountered a Cactus at mid-to-long range and we both had the benefit of cover. The Cactus was behind cover and set down a Potato Mine before she started returning fire.
I saw the animation indicating that the Cactus placed the mine, but I could not see the mine itself because the cover blocked line of sight but the Cactus was bobbing in and out of cover trying to do a charge sniper shot and my intention was to use the aim function and shoot her as she came out from cover.
In this instance "Aim Assist" continuously dragged my aiming reticule down to the Potato Mine (which was not even visible to me) so my shots kept getting redirected into the cover every single time I tried to aim at the Cactus.
After a couple of seconds of cat and mouse the Cactus evidently assumed I was a terrible shot and stood out in the open to charge up her sniper shot and giving me a clear shot at her, but because the Potato Mine was physically between us "Aim Assist" decided that I simply must be trying to shoot the mine even though I had no line of sight to it and my reticle continuously bounced away from the cactus and back to the mine every time I corrected.
Needless to say I got Spike Shotted and vanquished which allowed me to immediately turned Aim Assist back off after I respawned.