Azindel's Feln Control

I've put together this deck right after the Vara nerf, and I find that performs surprisingly well, even better than how classic Feln Control performed pre-patch.

It is, however, something completely different from the old Feln Control. The plan is to control the board until we drop Azindel's Gift, followed by a Black Sky Harbinger and ideally a Recurring Nightmare to kill our opponent while we keep removing their creatures.
As you may easily guess, this deck relies a lot on knowing what your opponent is doing and punishes your own mistakes very hard.

While I've refined this deck a bit during the last days, there's probably a lot of room for improvements. Also I've played only at Silver/Gold, hence I don't know if it would be still as effective in Masters.

EDIT
I have made a bit of changes to the deck, and I think it flows better now. Rain of Frogs allows a better hand control, allowing us to remove some threats before they hit the table. Feln Bloodcaster is a nice early blocker and together with Rindra, the Duskblade allows us to save precious removals and to put some pressure on our opponent early on, giving us the time to clean the board or drop Gift. I removed the matchups sections since it no longer reflected the deck.

Card Choices

Removals: Quite self explaining, we need a lot of those to be able to reliably control the board.

Draw: We obviously need to try to mantain card advantage, get the right answers for the enemy threats as soon as possible, mantain a smooth mana curve until turn 7, hence we can't play less. After some testing i think Herald's Song is better than the alternatives, since it enables us to cycle cards we don't need.

Devastating Setback: Very versatile tool that allows us to deal with grenadins, control our opponents hand and clean the board when paired with Witch, all in one card

Withering Witch: Some might think this is a wasted slot, and they wouldn't be totally wrong, but it's the only recovery tool we have for when we fall behind with removals.

Black Sky Harbinger: While Recurring Nightmare is a better finisher, this card allows us to recover hp, clean the board when paired with Witch, block creatures and, in general, keeps us alive.

Recurring Nightmare: Very strong finisher paired with Azindel, since the opponent can't remove it with spells. However it dies to any creature and doesn't recover hp (which we need in 90% of the games), so I wound't play more than 1, 2 copies maximum. It is especially useful to burn down Icaria and other control decks, which can win late game even with Azindel in play.

Azindel's Gift: Our win condition. Since we need to drop it as soon as possible, I wouldn't play less than 3 copies.

Celestial Omen: Tutor for either Azindel's Gift, Recurring Nightmare or Black Sky Harbinger, quite self explaining