The biggest change has been to my learning curve.
However just one zone change -WILL- transform a ships behaviour, and you're right, it's a tricky area thats taken time to understand.
I went back to the stock settings, drew every zones location on a piece of paper so i knew where they were, and tested different settings for compatible zones on the ships behaviour.
I've almost cracked it with all the big carriers, and the good news is that the Graf zep, Aquilla, Illustrious and Essex share the same zones and spheres.
Doesn't mean the Illustrious/Essex will react the same way exactly, but gives me a good start on them
The Glorious has a number of extra/different zones, and, being lower and wider, is inherantly more stable, but i've almost cracked it there too.
If i've figured it correctly, for a particular zone, multiplier applies to armour levels or hit points.
flotability: is a percentage in relation to bouyancy characteristics of zone
Hitpoints: is self explanatory
Destructable: self explanatory
Armour level: is obvious, unless it's -1 (linked to hull armour i think)
critical flotation: is a percentage of criticality to ship bouyancy, as opposed to just the zone
critical: determines whether zone flooding/destruction is definitely critical to ships total bouyancy
critical chance: is percentage probability of area flooding completely, or percentage of criticality to total bouyancy
flooding time: in seconds
cargo type: cargo, or not, in zone
crash depth: depth at which zone completely floods, or is destroyed.
I don't know for sure how accurate those explanations are, but in the absence of official definition, that's what they mean to me.
Seems to kind of work out in practise.
Edit:
In the case of the multiplier, it may have conditions to maximum values of other areas, so it could apply to critical chance, flotability, hitpoints or armour levels.
Basically the higher the multiplier, the tougher the zone, or the more critical it is.
I think