ok, I noticed a few things you may want to consider.
If you looking for a single target max tps spec... try this http://wowtal.com/#k=_Az2PG5.aei.warrior.
But keep in mind you will need eaither a secondary spec for aoe/utility tanking or you will want to respec to accomidate each situation.
Id take a look at your expertise. i see you running with 3 at the moment. I know hit/expertise isnt a major issue right now, but even a rating of 10 should show you a huge improvment.
what dose your opening rotation look like?
PS- I noticed a lot of things you can work on aside from threat, If your interested in hearing those aswell.