I play a DK Tank now, used to play a Warrior Tank pre 3.1 hope that gives some perspective.
IBF was overpowered to begin with so it being brought to 2 min simply means it's being brought more in line w/ the other Tank cds. Crap, my Warrior still is stuck glyph + 2 talent points to just get to 2 min. Personally I think 2 min cd's on the big "Oh shit" ability should be universal, there's no reason Warriors need to pay a ridiculous cost just to bring themselves in line w/ all 3 other tanks base standards.
5% armor nerf simply brings DK's armor in line w/ the other 2 shield wearing classes. Though you could argue the miniscule dmg reduction Block offers actually covered that differential. I'm not kidding even a 30k hit 1.5k BV is a 5% dmg reduction, while it's less consistent it still is a percentage worth noting if you're looking at armor reduction + Block vs just armor reduction.
The 10% hp to 6% stam change is noticeable. It actually brings us to about the level of Warrior hp. The problem is that Warriors had the lowest hp out of the 4 to begin with. Personally, it seems like it's a little extreme to reduce our health that much and Warriors actually needed a hp buff considering they had the lowest EH and also Blocked less consistently making their damage intake more spikey than the other 4.
So in short IBF was a long time coming, I'm surprised it took THAT long for them to change it. However, the combined 5% armor and 6% stam change seems one appropriate for the most part. Pre 3.2 we pretty much had it all. Awesome EH and great avoidance, now we're pushed slightly further to having slightly better Avoidance at the expense of a minor reduction in EH. From the looks of it thinks are relatively in line, though as we've seen EH seems to be favored for progression fights. Then again it's just one factor.