I was wondering if those of you that know what your doing could shed some light on my current build/gear. I have started to run heroics and while I am defense capped I am still having survival issues. Last night in heroic UK I could not keep agro from an undergeared DK. I have never had issues with threat and I was wondering what tips you guys had.
Wow. You're right about where I was gear-wise when I started Heroics. But a few things you could change.
Boots- Get Revered with Wyrmrest and get their boots, Sabatons of Draconic Vigor.
Chest- Revered Wyrmrest as well for Breastplate of the Solemn Council
Gun: Armor-Plated Combat Shotgun ftw
Gems- Switch the +agi in the legs for +Stam, or +Dodge/Stam
Trinkets- Get Seal of the Pantheon from regular HoL (Loken)
All of this should boost your def and avoidance way up, and give you room to swap some of those +def enchants for something more useful.
Beyond that you've got pretty much the standard talent build. Not sure why you're having threat problems, other than possibly a rotation issue. Or that DK was in frost or something.
It's impossible to tell why you have aggro problems without knowing more. For all we know, the death knight could have been running with frost presence (it's a common mistake).
Same with your survivability. There is a lot of stuff in heroics (including the "easy" Utgarde Keep and Nexus) that can kill you if tank, healer, or even DPS don't overgear the place and if you don't know exactly what's going on. In Utgarde Keep, for example, you need to understand to move away from time bombs before they explode if you have survivability issues on pulls involving strategists or to dispel flame runes. On proto-drakes, know that they have a Rend that ticks for 3k damage and they get a 70% haste buff from their handlers (which, combined with their two instant attacks, can make for some pretty awesome damage output on an undergeared tank). Use your mitigation abilities (Thunder Clap, Demoralizing Shout, Shock Wave, Shield Block, Concussion Blow, Spell Reflection, Shield Bash, Shield Slam [to dispel buffs], Disarm, etc.) when you have survivability issues. Note that sometimes it's not you being hard to keep up but the rest of the party taking so much splash damage that the healer has to leave you alone for a moment to keep everybody else alive. The reason for you dying may be your gear, your healer, your DPS, taking unnecessary damage, or a combination of the above. The first step to fixing this is knowing why you died. Get Recount or another addon that allows you to replay deaths and see what killed you, then avoid the causes for your deaths in the future.