I think most of the cards mentioned might be really good, perhaps even deck-defining... with the exception of the Warlock-legendaries.
Why? Because discarding cards in Hearthstone is, and has always been, a total crapshoot, simply because you always discard random cards. Now, if you could actually CHOOSE which cards to discard, even if it was only from one particular card, these legendaries would be marvelous. But you can't, and so you have to pray to whatever god or equivalent you believe in that the right cards are discarded, and not, say, your Cruel Dinomancer which was meant to bring out the Doomguard you accidentally discarded three turns ago. And even then Clutchmother Zavas is still just a potentially big minion. No Charge, no Taunt, no Battlecry, no nothing. One single target removal and it's gone.
I suppose we'll have to wait and see, but so far nothing suggests that Discolock will take off, in spite of Blizzard's insistence on introducing more cards to support the archetype. Because it's far too risky to play when you can just go for a more reliable deck, like Zoo or Handlock.
