Crouch - jumping actually works.

Standing up after crouching is a little bit buggy currently^^ So the crouch-jump ist theoretically also just a bug We can implement something like that if desired, but if not, it will be removed soon

i think we should be able to jump a little higher maybe 2 blocks high or 3? as taking a basic aspect of real life if you cant jump one block something must be wrong with you

Athlete have trouble jumping 1 meter(2 blocks) into the air, most records in the vertical unassisted jump are around 1.25 meters (2.5 blocks), and I didn't see any claims that exceeded 1.5 meters(3 blocks).
The average vertical is 50 cm for males, and that is one block. You can get more clearance by pulling your legs up at the loss of some of the vertical, and then you are crouched not standing on the new elevation. Higher jump capabilities in games is to compensation that they cannot climb something they would be able to in real life.

A character 3.5 blocks tall and jump of 1 block and an additional arm reach of 1 block, should be able to scale at least 5 block tall wall, with running jump and stepping on the wall could reasonably extend that to 6-5 blocks(3-3.5 meters).

Wow technicalities, personally though for game balance I think you shouldn't be able to jump more than 1 block or 2 blocks at most.