Dark Intimations

Oracle Text
Each opponent sacrifices a creature or planeswalker, then discards a card. You return a creature or planeswalker card from your graveyard to your hand, then draw a card.
When you cast a Bolas planeswalker spell, exile Dark Intimations from your graveyard. That planeswalker enters the battlefield with an additional loyalty counter on it.
Card Rulings
2/9/2017 When Dark Intimations resolves, first the player whose turn it is (if that player is an opponent) chooses which creature or planeswalker they will sacrifice, then each other opponent in turn order does the same, then all chosen permanents are sacrificed at the same time. Then each opponent in the same order chooses a card in their hand without revealing it, then all chosen cards are discarded at the same time.
2/9/2017 Each opponent chooses a permanent to sacrifice from among the creatures and planeswalkers that player controls. You don’t choose which type of permanent the player has to sacrifice.
2/9/2017 If an opponent can’t sacrifice a creature or planeswalker, that player still discards a card if able. You still return a creature or planeswalker card to your hand if able, even if no opponent sacrifices a permanent and/or discards a card. You still draw a card even if you can’t return a card to your hand.
2/9/2017 You choose the creature or planeswalker card to return to your hand while Dark Intimations is resolving. No player may take actions between the time you choose one and the time you put it into your hand.
2/9/2017 If two or more Dark Intimations are in your graveyard when you cast a Bolas planeswalker spell, you’ll exile each of them and that planeswalker will enter the battlefield with that many additional loyalty counters.
2/9/2017 The draconic Planeswalker Nicol Bolas is not featured in the Aether Revolt set. He must be up to something nefarious elsewhere.
1/19/2018 There are many important moments in the story, but the most crucial—called “story spotlights”—are shown on cards. These cards have the Planeswalker symbol in their text box; this symbol has no effect on gameplay. You can read more about these events in the official Magic fiction at http://www.mtgstory.com.
Removal that draws cards has pretty much always been good. Yes, Sacrifice isn't as good as Destroy, but it's still pretty good unless you're dealing with token spam, in which case there are plenty of other options out there to solve those particular problems. But if you've been maintaining board control, this card can basically single-handedly seal the deal mid game.
Does it generate card advantage? Totally. As you said, you get a net +3. Compared with a similar spell like Dragonlord's Prerogative, the slight reductiom in price doesn't (to me) seem worth sorcery speed, three colors, and the ease with which some of that value can be lost. The fact that this card advantage fails to kill or dig in an effective manner also makes me question how "good" it is.
In the current standard, I have a hard time thinking of anything that can match this in terms of raw advantage. If nothing else, people will try to make this work and it will make tournament appearances. Further, this card sounds pretty entertaining for use against control decks that try to win off of one or two torrential gearhulks. Even so, the value doesn't feel... useful.
This might just be foreshadowing.
3 card advantage for 5 mana at sorcery speed is fairly good, look at tidings or something. However this is better than draw 4 cards when it works, killing something of them is much more value than drawing a card, getting something from your graveyard, with options, is also better than drawing a card. Them discarding a card is slightly worse than drawing a card though.
But overall IF this works it's better than 'draw 4 cards', the big IF though is that they need a creature or planeswalker but even without that it's better than 'draw 3 cards' which is fine. The tricky thing is that a deck interested in a spell like this needs to be having creatures in the grave, that might actually be tricky but if that deck exists that will see play.
The bolas clause might be nice but completely depends on a good bolas walker of course. But even without using that clause entirely this card could be good enough if a grixis control deck has some creatures that will hit the bin often and a 'sacrifice a creature' effect is well positioned.