I have abit of gold to spend, and I'm wondering if Signet of the Accord or Bracers of Dalaran's Parapets will be worth it to buy. Personally I'm a bigger fan of the bracers, as I hate Old Kingdom.
Also, I'm having slight problems with threat at times(might be a skill problem though.) Should i take points out of deep wounds and anger management to place into cruelty?
Lastly, is there a minimun avoidance to achieve before entering raids? My guild tells me that i need a 60% dodge+parry+block as a minimun, but i haven't seen anything about this in tankspot. As a result, I haven't stepped into a single raid besides voa10.. Am i geared to raid?
In my opinion, your gear is good enough for Nax10. My guild ran Nax10 in Heroic/Crafted/Level 70 gear. We cleared Nax in our first week. But again, if you're going to be running it with super geared DPS, you might run into a few problems keeping mobs off of your raid. You could easily OT Nax no problem, but warriors are not he most desired OTs.
Levels of avoidance aren't the main focus for stepping into Nax for your first time, imo, but rather having good EH is. Also threat generation is important if you're running with high (3k-4k) DPS. As to your spec, it looks good, I would suggest putting 2 more points into Focused Rage. I know that 2 less rage per ability doesn't seem that appealing, but it could help with your rage management and in turn allowing you to have more rage to establish more aggro on mobs. I'm not that big into specs, because I think people should spec to what works best for them (unless they don't know what they're doing), but it's an idea.
If you don't mind me asking, what rotation are you using on Trash? Bosses?
I would say that the Bracers are probably worth buying over the ring. From my experience, bracer upgrades have been hard to find. Bracers of the Herlald (OK - H) finally dropped for me about 2 weeks of running it consistently. I've never seen Minion Bracers drop of trash in Nax10. Rings, on the other hand, I think are easier to come by. We've seen Deflection Band drop multiple times in Nax10. Also there is an epic ring from Heroic DTK, Keystone Great-Ring, that is worth running for. So comparing the drop rates on the potential upgrades for you, I would say you have a better chance of getting a ring from drops, rather than Bracers.
So your threat issues have been occuring on Bosses? The rotation you're using is fine, so I see no issues there. Just keep practicing and keep an eye on that threat meter to get an idea of the TPS you're doing and how any changes (you might do) in your rotation could maximize your TPS.
I know this has been a big subject lately, but I find myself queing Heroic Strike after every Revenge, which definitely helps my Threat on bosses (if glyphed, Glyph of Revenge).