Let's start off with Glyph of Blocking. Since Shield Slam is a standard part of prot warrior aggro, this glyph is effectively a 10% increase to block value. 10% from a glyph. That should be overpowered. But it isn't.
Let's move on to something that should be even more OP: Libram of Obstruction. This gives even more BV than the previous glyph, though it averages to about the same amount depending on gear. But with some luck with timing and avoidance, it will be up every time you block. And yet, this libram needs no nerf.
Getting back to warriors: Shield Block. Now what can possibly not be OP about DOUBLING BV for ten seconds every 60? That should be a powerful CD. Average it out and it's stronger than either of the previous non-OP items, but with even more flexibility than the libram. OP? Should be, but isn't.
But what's all this increased BV for if you can't block? The clearly OP ability to compensate if Holy Shield. In decent gear this means that every single hit will be blocked or avoided and even more, it does damage to the enemy. Somehow, that fails to be overpowered.
Alas, you're a warrior so you can't get holy shield. Fear not! You can get a constant 4.51% block increase from the trinket Lavanthor's Talisman. And that on-use, 440 BV! Stack that with shield block and glyph of blocking and you would appear to be nigh-invincible and generating more aggro than you can imagine. Strangely, only the latter is true.
But warriors clearly don't block enough still, so let's give them a talent that is really OP: Critical Block. 30% chance to block twice as much. Imagine effectively a 30% crit talent, wouldn't that be pretty OP?
Perhaps even with the trinket warriors still aren't blocking everything, so let's give them a nice low talent to help: Shield Specialization: 5% higher block chance and 2 rage from blocking. Notice how warriors are getting built up to have tons of block chance and aggro and wow, how is this at all balanced?
Let's just finish it up with Damage Shield and make every single enemy attack either avoided or do damage to them based on that clearly massive block value.
I cannot imagine how paladins are remotely balanced with so much block and all the aggro from it. But warriors, they must be even worse! Are the devs blind? Can they not see that with talents and items they have built warriors into massively blocking aggro machines, unable to be more than scratched by even the mightiest of foes?
What? Oh. People are running around with 1.5k BV and bosses swing for 20-40k? Damn.