Mac Cursor Bug
[CLIENT/GAMEPLAY] Adjusting the in game cursor speed/sensitivity does nothing.
It seems even if you have "use software mouse" unchecked the cursor inherits the sensitivity settings from your OS.
I use very sensitive mouse settings for my work but that sensitivity is not ideal for last hitting minions in lane, under pressure. At first I thought the mouse was just jumping around, maybe frame rate issues, maybe lag? I eventually figured it out when I got desperate and just turned the sensitivity all the way down to zero (in-game) and realized it didn't have any affect on the speed of my cursor.
Workaround
If you just turn down the sensitivity of your mouse in mac system preferences it fixes the issue. It's not as fine tuned and isn't as synced with the camera move/mouse sensitivity are in client but it gets the job done.