Tanks still need to hold threat, it's just that it's really really really easy to do so, even if you don't gear for it.
If you're referring to DefStats, it's the Hit Table Coverage that you want to get to 102.4%. The Total Avoidance is simply (If I recall correctly), your dodge + parry chance.
You're mostly on the right track in terms of gear, there's a few things I'd do differently though.
1: On your chest, reforge the dodge, not the parry. Maximising your mastery (Until 102.4%) is more important than balancing dodge/parry and you'll get more mastery that way.
2: You should only ever gem parry, mastery or stamina. Never expertise, never hit, never strength. Your weapon should have a mastery gem (The socket bonus is useless, ignore it), and until you hit 102.4%, all your gems should have mastery. Basically, provided the socket bonus is worth it (Which, when tanking, it almost always is unless it's a threat stat such as expertise or strength or hit), you should be gemming:
Red socket: Parry/Mastery Fine Ember Topaz
/Fine Lava Coral
Yellow socket: Mastery (All your JCing gems should be this) Fractured Chimera's Eye
Blue socket: Stamina/Mastery Puissant Dream Emerald
/Puissant Elven Peridot
3: I realise Soul Casket has Mastery, but seriously, just don't. Get Impetuous Query
or, better yet, Mirror of Broken Images
from Baradin's Wardens in Tol Barad. It's an amazingly good trinket.
Your spec and glyphs need a bit of work too, to be honest. Improved Hammer of Justice is a PvP talent and has no use in PvE. Eye for an Eye is a pretty meh talent that doesn't do much, same with Hallowed Ground and you should either have Eternal Glory or Seals of the Pure, never both. Seals is slightly better than EG, but really, you only take one of them because you have to to move further down the prot tree and they're both pretty meh talents. Pursuit of Justice (More run speed, which means you can change your boot enchant to the 50 mastery one) and Reckoning are both better talents to take.
Buuuuut most importantly. You must have Judgements of the Just. It's an essential talent. Yeah, it's slightly less useful if you have a DK in your group (They apply the same debuff) but it's miles and miles and miles better than Improved Hammer of Justice and there's no reason not to take it. And, even more importantly, you must have Ardent Defender. There's absolutely no reason whatsoever to not have Ardent Defender. It's an awesome skill and you definitely should have it.
As for your glyphs, the Glyph of Seal of Truth is really nice. 10 Expertise is a lot and, while I said you don't need to gear for it, it's your best threat glyph and is definitely worth picking up. For majors, Glyph of Divinity isn't very good for prot, it's a holy glyph, and glyph of Dazing Shield is another PvP one that, while it isn't strictly bad for PvE, can be annoying when you're trying to get a caster to come over to you and it's doing so very very slowly. I'd suggest Holy Wrath (Makes it stun elementals and dragonkins, which isn't useful in this raid tier, but is really nice in 5-mans) and the other can be swapped around depending on what you need at any time. Focused Shield is good for raid bosses, Ascetic Crusader has some uses if you die, Divine Protection is nice on some bosses and so on.