I saw a post on the Paladin boards discussing what would happen if Crushing Blows could not be pushed off the table. The obvious answer is tanking would become Bear country, as only Druids would be able to survive bosses.
For background, raid bosses have a 15% chance to deal a Crushing Blow, which does 150% of normal damage. If your total dodge/parry/block/opponent's miss chance is greater than 100%, you cannot be crushed. This relatively easy for a warrior to accomplish with Shield Block(+75% block), but much harder for a paladin with Holy Shield (+30% block). We do have Redoubt, which is another 30%, but that cannot be triggered reliably.
There are currently three ways to deal with Crushing Blows:
1. Not get hit by them. Dodge/Parry/Block.
2. Have so much armor that most of the damage is mitigated.
3. Have so much health that your healers have enough time to restore your health to full. This usually requires more healing.
Warriors and Paladins utilize the first strategy, while Druids use a combination of the second and third.
But as I was thinking about the problem, it occurs to me that there is a fourth strategy, just one that isn't used in WoW.
4. Prevent the mob from making Crushing Blows. This could happen through the use of a debuff. As an analogy, you can prevent mobs from casting spells through the use of a Silence debuff.
And naturally--since I am a paladin--my thoughts turned to using this idea to keep paladins in melee.
My idea revolves around Vindication. Make Vindication baseline, proc more reliably, (with a reduced debuff) and also have it reduce the chance of Crushing Blows by 15%.
So now having paladins in melee is very useful, as they keep the tank from getting crushed.
A paladin tank can easily keep herself from being crushed, but she has lower health than a warrior to compensate.
A druid tank can simply soak the crushes, the way they do now, relying on their armor and health.
A warrior tank, without paladin support, would be in a bad position. I would suggest some mechanism to remove Crushing Blows, only keeping it more onerous than a paladin's Vindication. Perhaps a debuff that they have to stack like Sunder (-5% per application), but which costs rage, causes minimal threat, and must be reapplied.
This way each of the classes have a slightly different twist on tanking. Rather than being strictly inferior in mitigation to warriors, Paladins have less health, but are immune to crushes. Warriors have better health and mitigation, but their crush immunity is clumsy. Druids have the most health and armor, but get crushed all the time.
And having a paladin--regardless of spec--in melee is always a good idea.