Which means you're doing nothing but PUNISHING US for even daring to use abilities that sacrifice defense for attack while doing NOTHING to allow us to reduce our damage taken by increasing our defense. Furthermore from the looks of things you expect us to be fine and dandy with taking vastly increased damage from anything remotely higher level.
What? No. Them increasing the ratio cap means that increasing our defense is still going to have an effect, the problem before was that our defense typically got so low that it didn't matter if we used defense buffs or not.

EX: Enemy has 1000 attack
Ratio cap of 2.0: Enemies cap their attack on you at 500 defense. Since most DDs have sub-500 defense without any buffs, people just decided to put up attack buffs whenever they wanted. Defensive buffs don't push you far enough above 500 for it to be worth using.
Ratio cap of 4.0: Enemies cap thier attack on you at 250 defense. If you have, say, 400 defense, then berserking would actually pose a danger, and every point defense from, say, Defender would actually have an effect.

The defense adjustment wont' change zerging, it'll only make SCH/BLM stunning a requirement at everything.
There remains more to be done to fix tanking, of course, but if the change forces people to actually think twice about berserking then it has done its job. Ultimately with just these changes people who are playing smartly will still do offensive buff zergs for themselves out the wazoo, but that's sort of the point? "Smartly" is the operative word here.

Ever notice the community reps always drop stuff like this on the players on a Friday afternoon? Or is it just me?
They like to save bigger announcements for the end of the week, as far as I can tell. Give it time to be discussed over the weekend? Dunno.