there really isn't a whole lot needed when describing what the soft crit cap is, which simply put is when every time a normal swing lands, it crits.
active variables in determining the crit cap (assuming attacking from behind and soft capped expertise for dodges):
glancing blows: 24%
miss chance: 24%-hit chance
assuming soft hit capped at 8% it would look like this:
meaning the soft crit cap is 60%
being at the crit cap just means that gaining extra crit past that point isn't as valuable unless you are also getting more hit.