Get 3/3 in Improved Thunder Clap, and go 2/5 in Shield Specialization.
Remember to take full advantage of your abilities. If you're still thinking Shield Slam > Revenge > Devastate, you're missing out on a lot. After you go through your rotation and get 5 Devastates up, only use Devastate if everything is on GCD or to keep the debuff refreshed. Shockwave and Concussion Blow all generate more threat than Devastate, and should definitely be used as priority over spam devastates, even counting in the possiblity of S&B procs. In nearly infinite rage environments (Patchwerk hateful tanking), spamming heroic strike will definitely get your threat up there.
As far as stats go...once you get your expertise to 6.5%, work on hit until it's capped at 8%, then continue back on expertise.
You currently have more threat stats then I do at the moment. How much TPS do you generate on average? I say this because I don't really have an issue with agro, save Malygos. So if you think your threat may be under par, take a look at your rotation and see what's going on there.