I have some Hobart documentaries on tape and they all seem to point to a rather small zone of exceptionally bad weather in the larger picture of generally bad conditions. Mostly likely just because of this convergence of the two currents and the weather systems coming in from the southern polar ocean. Pretty much the boat outside this zone get bad weather but not of the magnitude that would kill them.
I venture that a small detour around such a bad spot bu a multi wouldn't hit its result to much and no boat is as slow as one that is on the bottom or sitting like a duck with all sails down riding out a particulary violant storm.
See it just like the dull drums, multi's can look for a passage through it along a much wider front than a mono hull can. As a result they can minimize the impact or slip through and escape the worst. I venture that finding a passage of relative mild conditions may be found in the same way.
In relation to Open 60's, I don't think these will hold up to well, They are designed to the extreme and they don't have much margin left. However the newer designs that are intended to participate in more ocean crossing races and the maxi cats should be able to.
After all Bass strait is bad but the Southern Ocean in general is bad and the maxi car have survive that one quite alright.
Wouter