The problem with "Instant OFF GCD" abilities makes combat feel less rewarding.

[complexxL9]

Please share with me a specific scenario where it's impossible to interrupt an ability with either an off GCD stun or Silence due to the animation lock. I'd love to hear it. And whatever you come up with (if anything) I can assure you I can give you advice on how to make it work.

Also share an example of RNG spike damage that's impossible to anticipate and results in a death purely because your benediction didn't go off the exact nano-second you pressed it and not because a tank didn't use a cool down or the ball was simply dropped healing wise somewhere.

Really? It's in the OP - http://youtu.be/40a_cnDQKeE

See that little "E" (3rd skill on 2nd hotbar) being pressed few times and not going off? See it being pressed at 00:04 just before the enemy cast is being finished and still not going off? Well that is Silence not going off and not interrupting one shot boss ability. Is that example good enough for you to stop your bunch of "these lame mechanics is how SE intended them" posts?
I don't care if it's by design if the design itself is awful.