Well threat can be deceiving. I think a post to your armory would help, as we can have a look at your current gearing/spec/etc. and give you some more tailored advice. What I mean by deceiving is that it will change between the different tank classes, and dps is not a viable means of calculating your threat output... ie. a warrior will put out far less dps than say a paladin would or a dk, but still hold aggro.
For the enchant, you can actually use mongoose as a threat enchant as well as accuracy, and it may have a bit more utility in terms of survivability as well. I personally prefer bladeward on my current weapon/gear setup, but it is a preference thing. I would say post an armory link and I'm sure people can give you some more advice.