This question has been solved 10 years ago.

Given the option, CV is never the best.

GPA gives you 86.5 avg dmg with the following breakpoints:
20 ias = 3.57 aps = 308.8 dps
37 ias = 3.84 aps = 332.2 dps
63 ias = 4.16 aps = 359.8 dps

CA gives you 91.5 avg dmg with the following breakpoints:
22 ias = 3.33 aps = 304.7 dps
35 ias = 3.57 aps = 326.7 dps
56 ias = 3.84 aps = 351.4 dps

CV has the same breakpoints as CA, but with .5 less avg damage, and one less range, so given the choice, CA>CV

Thresher gives you 76.5 avg dmg with the following breakpoints:
22 ias = 3.84 aps = 273.8 dps
42 ias = 4.16 aps = 318.24 dps
75 ias = 4.54 aps = 347.31 dps

Considering you want Crushing Blow to proc as often as possible Thresher/Giant Thresher is the way to go.
For any polearm without Crushing Blow it's either Cryptic Axe if you want damage per attack or Great Poleaxe if you want damage per second.

Refer to this link for the calculation of Fortitude or Treachery being better.
https://forums.d2jsp.org/topic.php?t=54233648