Literally the only reason Crit is stacked so heavily as Fury is to get BT to crit more. When you get BT to crit 100% of the time, Crit's value, for the ENTIRE SPEC, drops compared to other stats.
So, yes, it is the soft cap for all of Fury.
This. The reason its called a "soft cap" is because it is the attainable point we try to reach, before the effect diminishes sharply (just like with Hit/Expertise), so yes it is actually the soft cap for the Spec (and technically a hard cap for BT).