UPDATED: Sat Feb 11 2017:I no longer play Destiny and no longer have to concern my self
with maintaining parity between aiming mechanics of the two
games. My very latest settings are at the top, and the old ones
are at the bottom to preserve them in archives.
Mouse used is Logitech G502s connected to Xim4 with 20160405 stable firmware.
MOUSEDPI: 6400, at 500Hz polling
GAMEHoriz/Vert sensitivity: 100/100
Aim Technique: Exponential Ramp
Aim Assist: 50
Ana scope relative sensitivity: 100
Widowmaker scope relative sensitivity: 100
HIPSensitivity: 7.5
Boost: no boost
Steady-Aim: off
YXRatio: 1.0
Ballistic curve: no curve
Turn-Assist: my emote wheel keybinding
ADS (for Widowmaker and Ana)
Delay: 100ms
Sensitivity: 3.0
- This is 41% of Hip sens to maintain 1:1 pixel ratio between hip/ads aiming
Boost: no boost
Steady-Aim: off
YXRatio: 1.0
Ballistic curve: no curve
Turn-Assist: my emote wheel keybinding
Translator: Use Hip Translator
KEY BINDINGSTab - lobby
Caps Lock - ability 1 (sprint, hook..)
Shift - emote wheel
Alt - Weapon Switch (primary key bindings)
Space - Jump
Q - ability 2 (grenade, poison...)
E - melee
W - forward
A - left
S - backward
D - right
R - reload
C - crouch
F - ultimate ability (primary bindings)
Enter - ultimate ability (secondary bindings)
Pause/Break - Open Overwatch Menu
Esc - PS, console menu
Left Click - shoot
Right Click - aim down sights
Mouse Wheel - weapon switch (secondary key bindings)
OLD SETTINGS START HEREUnfortunately Overwatch feels much different from Destiny or Titanfall, it's a game with a steep exponential acceleration curve and the look mechanic feels different. It feels very floaty, best I can describe it is: "
like your sniper scope is glazing over a glass surface".
First breakthrough came from gunit2004 here[1] with a curve that cuts off at 40 which allowed him to retain maximum horizontal turning speed at high mouse speed without tripping the turn limit which happened to stay below the threshold of in-game timed acceleration feature.
Further experiments in that thread gave me an insight that I might tone down this effect with a decelerated curve plus extra sensitivity. It worked
for me, floaty feeling was reduced and the game feels sharper. Hip curve:
>>> XIM4 [Mouse Ballistics] START PASTE >>>
X4MB:AAAAGgA0AC4AMAAwAC4AMgAwADEANQAxADEAMgAwAAQJDRIXGyAkKS4yNztARUlOUldc:X4MB
<<< XIM4 END PASTE <<<
Curve will look like the equivalent of this image in your Xim manager. If you would like to test this curve divide your current sensitivity by 0.46 as your starting point and use the result as your new sensitivity. I can't say if DPI below 5600 will feel as good because enormous sensitivity settings might make the pointer skip too much:

I also assigned 8200DPI as the second setting of my mouse profile for when I want to play Lucio, Reaper or Tanks, but 99% of the time I play hitscan precision characters; Widowmaker, Ana, McCree... so this is just a small bonus, nothing special if your mouse doesn't support such on-the-fly changes.
GAMEHoriz/Vert sensitivity: 100/100
Aim Technique: Exponential Ramp
Aim Assist: 0
Widowmaker scope relative sensitivity: 100
Ana scope relative sensitivity: 100
HIPSensitivity: 15
Boost: 300
Ballistic curve: see image and code above
ADS (for Widowmaker and Ana)
Sensitivity: 10
Boost: 150
Ballistic curve: see image and code above
Translator: Use Hip Translator
References:1.
http://xim4.com/community/index.php?topic=47049.msg569044#msg569044