I have just entered MH and BT, and have found having a passively un-crushable set very helpful for a lot of fights, and I get positive feedback from healers all the time about it. I saw some other threads with people asking about items, so I will post what I am using here. These are by no means the *best* way to achieve un-crushable at my gearing level, but it is what I have.
I find it helpful right now, but perhaps someone more experienced in MH/BT can tell me if it will be good while progressing through these instances.
i didn't get enough gear to be passive uncrushable until our second shahraz kill when I got the shoulders. I tried it out but found it to be not all that amazing for much of anything. On the boss fights in BT/Hyjal where you might worry about dying, it's not crushes that will kill you (because most of these bosses can't crush anyway e.g. azgalor, shahraz) but parry-instagibs. Assuming your healers are up to snuff, it's far better to gem and enchant your gear for max stam rather than shoot for that 102.4 plateau, especially as you start getting 15 stam gems.
like people say around here, it's not about taking less damage, it's about being able to take more damage.
Yeah, I was gearing for max stam, and I still have all the gear in my bags, and use it for things like Kael'thas (23k buffed HP makes pyroblast survivable reliably without last stand/shield wall/consumables, just a priest shield).
The first fight I tried the above set on was Morogrim; who attacks really fast, and would every once in a while would tidal wave, block, block, crush and kill me. There were other elements of the fight to work out with murloc tanks and healers getting watery graved, and me just dying every once in a while was not helping. I put on this set and we havn't not one shot him for a while. Even when my healers get watery graved it is not an issue, because I have avoidance trinkets on, so I have so many use-tricks that it is not an issue.
On the first couple of tries of High Warlord in BT I used my max effective health set, but with the healing that everyone was doing for the bursting shield, people would not always get healed up because I was taking spiky damage, and MT healers couldn't afford to flex heal. Once I put on this set, I got bursted down only once (Which was my fault, I could have used a trick, but I was paying attention to everyone else's health).
It seems to have helped on these fights, but I have no idea what the future fights hold for me. Reading some bosskiller's strats makes me think there are some fights that require high effective health, other fights that require high real health, and some that this fights that this set might be helpful on.
Have you tried using an un-crushable set on Moro or High Warlord? I am curious to see if it is the nature of the later fights, or if it is just my guild's setup with healers, and whatever else.