How are models with 4-4 mov supposed to jump this high?

The way I've always played it (which may be incorrect) is that you still count the movement distance between the starting and position of a vault, so if you vault from ground level to a higher level (climbing boxes or if you have a TAG that can climb onto a building), the move distance would be measured from ground to elevation. This means that a 4" move that goes up a pile of boxes at a 45 degree inclination would only have moved 2.8" in the horizontal and vertical directions.

Vaulting the full 1st MOV value would therefore allow the trooper to efficiently clear tall but thin obstacles (walls/fences/etc), and leap onto short building, but climbing plus would remain the only option to efficiently scale taller buildings and would have the ability to maneuver horizontally around the face of the building.

If we want to fix vault/jump/super-jump to be both more useable and also more realistic, I would propose the following:

Baseline: Short Movement vault up to half your silhouette, Entire Order Jump allows vaulting up to your silhouette height and clearing horizontal gaps equal to half your 1st MOV.

Super-jump: Short Movement vault equal to your silhouette height and clear horizontal gaps equal to half your 1st MOV, Entire Order Jump allows vaulting up to your 1st MOV and clearing horizontal gaps equal to your 1st MOV.

Climbing Plus: Short Movement vault equal to your silhouette height. Entire Order Jump to clear horizontal gaps equal to half your 1st MOV.

 

Super-Jump is not that common, right? So can it be amazing (even if it takes a repricing)? Actually, isn't already pretty pricy?

Count of super jump units by the Vanilla Faction:
Pano: 5 (2 Characters)
Yujing: 4 (1 Character)
Arianda: 7 (Not including the Strelok Antipode)
Haqqislam: 3 (1 Character)
Nomads: 5 (2 Characters)
Combined: 4 (1 Character)
Aleph: 5 (3 Characters)
Tohaa: 3
O-12: 5 (4 Characters)

And would it be OP if it ignored Vaulting? With the exception of all the Arianda Dog-warrior variants, all the super jumping units are niche and special use. It would be nice to see them get a boost with some crazy unique movement abilities.