Honestly, I like wonky builds And tier sets will also lead to wonky builds for sure by changing how different synergies are weighted. THis will be a very unique experience for simulation script writers; the level of complexity is far greater than it was back in Cata or Wrath.
As for unique effects on gear. With borrowed power you would eventually get it. Legiondaries were the exception and early legiondaries were horrible for exactly this reason. Moving a lot of power into special gear that you have no safeguards for is a recipe for disaster. Just ask any rogue without Sylvanas' daggers.