Yeah... still sounds a bit niche. It's not common to not be able to attack something for 12 seconds with CS, much less with the frequency with wich we would need to make full use of it.
Again though, unfortunely i can't test it. But aside from some creative encounters, i don't foresee much of a use for it.
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Only requires a look at the talent trees to see Arms is by far better in terms of options. Ret is "broken" atm in alpha. But if you are looking for a viable PvP class, you can't go wrong with warrior. Ret was never a very good PvP spec.