(Note: This has also been posted on the WoW eu Forums. I'm looking to get a lot of different answers )

I've been reading up on a few forums, and speaking to many tanks about the direction that my gear is going, and most of the times, I've been going in circles.

The World of Warcraft Armory

This is my gear. At the moment, I'm collecting some more gear so I can create different sets, like Mitigation, AV and Threat.

Although my threat isn't low, per say, there are times where some of the huge nukers (mainly mages) have to slow down in order for me to gain some aggro again. However, on most fights like 'Heartbreaker', I can keep up with the threat.

What I feel is lacking at times, however, is my Mitigation. I feel like I take way too much damage. I hardly die, but I feel that the damage I take is way too big.

Also, I've had an array of different responses about my hit + expertise problems. Some people tell me to not bother going for the Expertise Parry cap and to stay around 26ish. Others tell me to go for it, and it gem all I can into it. Others tell me not to bother with gemming hit, and letting the gear do the work for me. What should I do? (Note: There is almost always a Draenei in the raids.)

And my last question, is to do with trinkets. At the moment, in my bag I have Gossamer and the Monarch Crab. Both are very useful, but I can't help but think I have focused on too many AV trinkets.

Albeit, I haven't had any others drop for me, but I'm interested in what trinket sets would do best for a;

Threat set.
AV set,
Mitigation set.

Thanks for the help all.