@fufibun
I'm glad there's someone else out there that seems to agree with me that there is no change between prepatch and postpatch exponential ramp. Honestly I think it's all just confirmation bias. I believe Blizzard's intent in having the old standard as a selectable option was that it would remain unchanged. Why would they keep an older option and change it, too?
I played all day, and while it was definitely jittery on Dual-Zone, Exponential Ramp feels exactly the same. I tested in the training area going all directions, diagonals included, and I experienced no alleged 'curveball' diagonals. I use default settings (EDIT: default XIM settings) for the most part, in case that makes a difference.
Unfortunately, we won't really be able to produce any physical evidence from prepatch, so people will probably keep believing it is different and whining about it.
If there is a change, the XIM devs will probably be the ones to find it.