I can't say I'm a fan of TBN, other tank CD's are always safe and powerful, TBN Is situationally more powerful but also weaker in a lot of situations.

I understand some people enjoy the "punishing" nature of it, I personally don't, thing is TBN is actually pretty good on autos, I've had it work on autos a lot before. (Ironically it might be harder to break with better gear because TBN scales with your hp which can be a blessing or curse) I think its not good that you lose damage for messing up a "defensive", lets say the boss wants to cast then enjoy losing around a GCD's worth of damage for using a defensive.

Personally I think TBN should Reward the DRK instead for proper usage with something such as a regen (As dark already lacks sustain).