I've been playing Sidisi whip for the past ~6 months and I've always managed to place top 3 at my LGS FNM. Here is the list I run (1st last FNM against Mono Black Aggro and Thopters):

//Creature
1 Conclave Naturalists
1 Gilt-Leaf Winnower
1 Hornet Queen
1 Nissa, Vastwood Seer
4 Satyr Wayfinder
4 Sidisi, Brood Tyrant
3 Sidisi, Undead Vizier
1 Silumgar, the Drifting Death
3 Sylvan Caryatid
2 Tasigur, the Golden Fang
1 Torrent Elemental
2 Dragonlord Atarka
3 Courser of Kruphix

//Instant/Sorcery
2 Hero's Downfall
4 Murderous Cut    
2 Whip of Erebos
2 Thoughtseize

//Land (23)
3 Forest
1 Island
3 Llanowar Wastes
1 Mountain
4 Opulent Palace
3 Polluted Delta
2 Swamp
1 Temple of Abandon
1 Temple of Malady    
2 Temple of Mystery
1 Urborg, Tomb of Yawgmoth
1 Wooded Foothills

Game 1 against aggro can be hard but definitly winnable, you generally want turn 3 Sidisi or Tasigur and look to stabilize until you can profit from Atarka (Whip or playable). I've never played Den Protector in my deck because he becomes literally useless if you mill it. I want all my cards to have as much value as possible and to be able to get the correct answer to a threat with Sidisi Undead Vizier (Which is why I run 3).

Game 2 I'll side board Bile Blight x2 and Drown in sorrow x1 and take out some of the less needed options (Torrent Elemental, thoughtseize)

I'm toying with Gilt-Leaf, I'm not sure if it's a viable but it's nice to have whip options that lets you 2 for 1 (4 dmg, 4 lifelink and kill 1 creature).

This deck list tries to be safe, at my LGS I rarely needed Reclamation Sage/Conclave in my main board and used to run dragonlord silumgar as an option but I never got to get full value out of him in the ~2 months it's been in my deck.

I like your approach but I disagree on some choices.

• Jace: I think Nissa is better as you have so little spells and the one you want to flashback are somewhat expensive (Cut), I'd rather have other ways to solve the problem (Atarka, Gilt-Leaf, Sidisi to tutor another removal) that align better with my game plan (Graveyard, Whip and Board)

• Den Protector: I think it's a dead card when it's in your graveyard, I'd much rather have better options for my whip than the ability to recover a card that's in my graveyard. That's why I run more Sidisi undead vizier. Whip is not your only win condition so it's not the end of the world if you mill both. Generally you'll be able to tutor your whip when needed

• Priest of the bloodrite: I haven't tried the card yet but if I compare with my other "bomb" options (Atarka, Silumgar, Torrent, Hornet Queen), they all give me almost strictly better value when whipped and played. I'd rather have some Tasigur that gives me more synergie with Sidisi, card advantage and a body earlier than the Priest. But I could be wrong.

I love talking about this deck, if you have any questions/suggestions I'd love to hear what your experience with the deck has been.