Issues - what this suggestion tries to fix:
1. Climbing up and placing ladders as you go is cumbersome, placing a ladder while going up requires use of crouching, which results in the player going down the ladder, potentially missing the block they were trying to place a ladder on.
2. There currently isn't a binding for locking height on a ladder, such that a player may go "forward" but not "up", think of climbing sideways while looking to that side.
Suggested Fix
1. Change "Go down ladder" binding to "Sprint" button, as it has no current use while climbing a ladder (if i remember correctly), and is not unintuitive.
2. Add a new binding to lock height on ladder, set it to "Crouch", this could also be used to stay on ladder and not fall off if climbing to much to the side, so one could "hang off the side" of a ladder, for building or similar purposes. This should be consistent with the purpose of crouching on-foot.
Problems - issues with these suggestions:
1. I propose 2 changes, to be done together, while i believe it is for good reason, i hope this won't come off as rude.
2. This adds a change in game feel as players may now climb faster than before, the suggestion #2 was added to kind of remedy this, making players not move as fast as if the ladder was placed beforehand, or as fast as a player chasing/following them.
3. This behavior is inconsistent with creative flying controls, personally this is not a big issue as i don't switch gamemodes often, but this should still be considered.