-1 Azami
+1 Hapless researcher
Works the same, but you can even play Hapless Researcher from your hand, if that's required, saving a Cabal Therapy for other purposes. Also, in an hypothetical and strange pairing, Legend Rule doesn't screw up all.
-4 Gitaxian Probe
-2 Street Wraith
+2 Cabal Therapy
+2 Pact of Negation
+2 Chancellor of the Annex
Gitaxian Probe and Street Wraith were only here for his drawing capabilities. But this cards make more difficult to mulligan, while don't assure you the necessary draw. Is better a mulligan to find the correct hand than a hand with one or two cantrips. And I feel that I need more defensive stuff to protect the combo.
With a whole Cabal Therapy playset in your graveyard, peek opponent's hand with Gitaxian Probe is also unnecessary. You can use the first one with a wild guess, the next one will hit just on the spot. You don't need to worry about the Therapies costs messing with the Dread Return cost thanks to Bridge from Below, so... why don't use all of them?
-2 Cabal Therapy (Sideboard)
-2 Pact of Negation (Sideboard)
-2 Chancellor of the Annex (Sideboard)
Therapy, Pact and Chancellor are all promoted to the main deck.
+4 Nature's Claim (Sideboard)
It's the only reliable way to get rid of some annoying Graveyard Hate, like Leyline of the Void or Tormod's Crypt. At least, the cheapest way to do so, with an acceptable cost.
+4 Leyline of Sanctity (Sideboard)
For those turn-one discard cards. Blackmail, Cabal Therapy, Despise, Duress...
