I have noticed a little decrease in my threat, presumably from loss of Rune Strike frequency (in addition to the 10% parry lost I down-graded avoidance slightly in my tank set for a GOB more health).
Judging by your armory, the first 2 things that jump out are Expertise and Avoidance. Your expertise is significantly below the soft cap, meaning any melee moves you throw are getting dodged/parried about ~15% of the time, so that'll hurt your melee, ScS, BS, and PS threat noticeably. The soft cap is 26 and up to that point you'll see a lot of improvement in your threat as each bit is a double whammy on the moves I mentioned. Avoidance (principally you'll get this by getting more real tank gear, less pvp gear, and getting rune of SS when your gear can support your def cap without SSG) will greatly improve your survival (since you can expect to get a good 8-10% more from full Naxx gearing), but it will also noticeably increase your RS proc rate. Provided you use RS well, that is a major threat component.
If you want to squeak some more threat out of your talents, you're doing ok now, but one thing that is unequivocable: drop 1 pt from 2h Spec and finish Rage of Rivendare. Even without that additional 1 Exp (worth 33 rating from gear), 2% ALL dmg trumps 2% weapon dmg without question. BcB is fine on threat but with your gear if you're trying to do Uld10, I'd move those two points to Dirge. If you're using Reaping well, I'd wager you're trying to spam ScS frequently, and the additional RP will buff that threat and make it easier/cheaper to keep UB rolling. If you pick up CE it will give you a noticeable threat buff on trash as well, though it's frequently under-used by the people who take it.
Beyond that it is all a matter of proper use of abilities. As an Unholy Knight, your strength in threat relies on heavy stacking of passive effects while using your single target strikes smartly to get focused threat where you need it. So, you want your diseases and UB on hitting every target all the time. DnD is good, but use it judiciously, it's generally great for the start of the pull when you can set it slightly in advance and get ahead on the rune CDs before you start full in on the targets. UB should be up and ticking at all times. ScS and RS should be your work horses after that, and will pass diseases up for total dmg done. If your gear is well setup, using avoidance smartly, RS will easily top your threat abilities, but it is best used macro'd into several other moves and click those buttons even when they're down to make sure RS fires immediately as it procs. For Unholy I macro'd it into PS, IT, BS, and ScS, but you can figure out what's smartest for you.
So, where specifically are you having threat problems. What fight(s), what scenarios?