This:
Run up to a wall, press C and your character will vault over it ( JUMP control ). Different vaults actions depending on what type of wall.
If you are not near a wall your character will simply jump and down.
( So this is proximity sense function. You are close to the wall, and you are pressing C. Special action happens. )

Now consider this:
Run to a ladder and press C and hold FWD. You climb up the ladder. Too easy.

Climbing ladders should be the same as JUMP. Why would it be any different ?
In fact you could just run to the ladder and automatically start climbing. Just saying....!!!!

What ever the system is that we have had to suffer since ARMA in the beginning, it has always been annoying to use.
Looking around to catch the ladder Ikon is just plain bad.
If you are at the foot or head of the ladder, there is ONLY one thing you want to do.
Imagine if you had to do that to climb a wall .... boring!

A lot of functions in game could be changed to proximity sense. Opening doors etc etc.
The C button could do all of them. The proximity to the ladder, door, car door decides what is to be done.

Thanks! :- )