There is no hardcap for Monk crit in FF14:ARR except 100%, and the only "softcap" for crt% is, what, 70% because IR takes you over 100%.

WoW originally (don't know if it still does) has the example for crit% where crit% below a certain point would convert "misses" to "crits", but after a certain point would only convert "hits" to "crits". That may not actually be 100% accurate -- the WoW hit table was pretty involved and there's a lot of random stuff about glancing blows and other things shifting and using up "hit table space". The concept applied though -- below/above a certain threshold, the value of crit changed because it actually did something different. Bottom line is that the crit softcap there was a result of the way the hit table was constructed.