Sensei's Divining Top - This card has lots of busted interactions, like
Future Sight/
Bolas's Citadel/
Intet, the Dreamer, and lots of very strong interactions like
Rampant Growth/fetchlands to clear away currently unwanted cards at no extra cost. If your deck can do any of these things consistently, SDT is great. But I see it going into a lot of decks that CAN'T do those things at all, let alone consistently, and it's just not good.
Think of it in comparison to
Night's Whisper in the early game; let's say you are trying to avoid mana-screw or mana-flood. You play Top on turn 1, peek on turn 2. You've paid 2 mana spaced out over two turns to look 3 cards deep for the land/nonland you need. That's a slightly better deal than simply playing Night's Whisper on turn 2, both in terms of mana efficiency and card selection (you have now seen 12 cards using Top, only 11 using Whisper). However, every turn after that if you are still trying to hit lands / nonlands, in order to keep ahead of the Whisper player's depth of cards seen, you need to keep paying. Having simply drawn the cards is way more efficient in the long term, even if you didn't want either of them but are just trying to find cards deeper into your library.
In addition to that, Top slows down the game for the rest of the table. So it comes at a cost to the fun of the table in addition to the costs of your own deck's efficiency.
Brainstorm - Basically everything I said about Top, except it doesn't slow the game down as much because you only cast it once.
While I'm on the subject of "cost to game pace" . . .
Sid the Chicken wrote:
The reason Reliquary Tower isn't an auto-include in every deck is that not all decks can sustain a large hand size and still be impacting the game, but the decks that CAN do this will love the effect.
Something to note, Reliquary Tower can either speed up or slow down gameplay, usually inversely proportional to how good it is in the deck. That is, if it doesn't do much in your deck other than let you skip deciding what to discard when you're at 8 cards, that's good for the pace of the game. But if you have 12 cards and each of them might be relevant to the situation and you're trying to see the optimal line of play at each moment, that's actually going to slow it down for everybody else. So while I agree with Uktabi_Kong that it's an overrated effect (especially in groups that run lots of Wheel/Twister effects), I'm actually kind of
glad that's the case.
Wrath of God/Damnation - These cards are perfectly solid, but it always feels bad to have one of these in my hand while staring at an enemy indestructible creature, or
Obzedat, Ghost Council,
Rekindling Phoenix, or even just a heavy hitter with flash and/or haste sitting in my opponent's Command Zone (
Chromium, the Mutable,
Samut, Voice of Dissent). With these resilient creatures being so popular in my experience, and WotC printing more types of Wrath effects that are either better at answering indestructible (exile, -x/-x, tuck), or being instant-speed (
Fated Retribution,
Consume the Meek), or both (
Settle the Wreckage,
Aetherspouts), it gets harder to justify good old WoG. There are even a few which get around indestructible AND are cheaper than 4 mana, like
Toxic Deluge and
Slaughter the Strong. Even if I had all the above alternatives in my colors and were looking for MORE wrath effects for my deck, I would still prioritize ones with high flexibility, like
Cleansing Nova/
Austere Command/
Merciless Eviction, or ones that give extra benefits or are one-sided like
Plague Wind/
Decree of Pain/
Martial Coup.