...to talk about the card that everyone is losing their shit about;
I love Time Walk effects. If there was a good way to take advantage of extra turns in Standard, you know I'd definitely be playing it in my deck *o* Time Sieve, Time Warp and Emrakul were all present in my decks when they were Standard legal :D
Lets not even get me started on casual formats like EDH Commander and Chromatic *_* Everyone likes taking extra turns, in any game. That's why, like drawing seven cards, whenever a card with "take an extra turn" is printed on it, people lose their shit @_@ It is currently hands down the most expensive card on Starcitygames' list, and for good reason; everybody wants this card (to be good)!
But is Temporal Mastery good?
To answer that question, we'll first have to understand what makes this card seem so good in the first place; the Miracle mechanic. Grab a chair and take a seat, breaking down this one is gonna take some.. time :P
You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.
Basically, this mechanic works a lot like Delver of Secrets :D What you should do is; whenever you're going to draw your first card for the turn, you set your hand aside (or in your other hand) and look at the first card as you draw it. If it's a miracle, thank god or whatever divine entity you worship, and decide if you want to cast it. If you want to, tap your mana and cast it then and there ^o^
Otherwise, if you put the card you draw into your hand and then decide that you want to make it a miracle, you might instead get a judge called on you and then you'll be actually wishing for a real miracle to get out of the mess of a situation that you're in +_+
and god forbid if you drew two cards at the same time (with Howling Mine for example) and put them both into your hand.. and then you try to cast a miracle.. ugh +_+ I foresee lots and lots of judge calls because of something like this happening.. especially since I suspect Howling Mine will be reprinted soon.
So save yourself, your opponent, and your friendly neighborhood judge all the trouble and don't fuck up your miracles >:|
Now, unlike Delver of Secrets, miracles don't happen only during your upkeep draw step. It says "the first card you draw this turn", so miracles can happen during your opponent's turn too! (with the help of instants like Think Twice)
From what we know so far, miracles seem to be your run of the mill, standard instants and sorceries stapled with the new mechanic. In fact, I wouldn't be surprised to see a wrath effect in white or a rampant growth variant in green. I hope there will be nice surprises like a green creature with miracle, though *o*
It also looks like miracles will have ultra-high mana cost but have really, really cheap miracle costs, which makes them sort-of anti-Leylines; they'll really suck in your opening hands but are the awesomest topdecks ever (I for one am looking forward to another topdeck of the century come Pro Tour Avacyn Restored). Like all cards that would suck being stuck in your hand, miracles are great discard fodder and work well with cards that put them back into your library.
Knowing this, though, makes me think that miracles will most likely be spells that aren't supposed to have decks built around them. You could certainly lean your card selection in a certain way to make the most out of your miracles, but building a deck aimed solely at casting miracles as often as possible looks to be extremely unlikely ^^
Examples of considerations during deckbuilding would be thinking twice about putting multiple card draw spells like Blue Sun's Zenith or Divination and instead focus on singular, instant speed card draw like.. Think Twice (which, in case if you haven't realized, is potentially very good with miracles)
Think Twice doesn't only allow you to cast your miracles at instant speed, it also doubles your chances to cast them; once during your draw step, and once during your opponent's turn :D (though it would kinda suck when you end-of-turn Think Twice on your opponent's turn and have no mana up to cast the miracle you've just drawn.. sadface)
Blue's card selection is also really great with miracles, namely this card;
Ponder has been paired with Temporal Mastery since the moment magic players first laid their eyes on the blue mythic; Turn 1 Ponder, putting the mastery as the third, and casting it on turn 3's draw step, netting what is effectively an extra land drop and an extra card drawn?! Free explore!! wow whee! *O*
Not to mention how seemingly broken this would be in the only competitive deck currently running Ponder; Delver Tempo. Imagine a turn 3 Temporal Mastery, flipping Delvers, netting extra mana and getting to bash twice.. Crazy tempo boost @_@ Thinking about how Temporal Mastery would make the already 'most powerful deck in Standard' even more powerful suggests that the mythic would most definitely be banned not long after it completely dominates Barcelona..
There are a few drawbacks of the miracle mechanic; you have to tap mana and cast it during your draw step, effectively rendering it to sorcery speed. The only other two cards with miracle spoiled so far are removal-type effects that are usually better saved and cast as instants because you might not always want to cast them when you draw them in your draw step, either because you have no use for them or because you need all your mana on your turn to tap out for something more important. And when you don't make a miracle out of your miracle spells, they tend to get stranded in your hand because of their horrendously expensive mana costs.
What is super powerful about Temporal Mastery isn't just that it is cheap, (in both senses of the word) it also mitigates the drawbacks of the mechanic. You always, always want to cast Temporal Mastery if you have the mana for it.
Getting an extra turn basically makes the spell free and any other mana you have available becomes free mana, you also get to do everything else twice. Don't even get me started on how crazy casting Think Twice at the end of your opponent's turn into a Temporal Mastery can be @o@
The only bad time to draw Temporal Mastery seems to be turn 1 on the draw, turn 2, and when you don't have mana to cast it. Every non-miracled Temporal Masteries will also be stuck in your hand as horrible dead weights, at least until turn 7 (provided you hit all your land drops).
And while a turn 3 Temporal Mastery seems like a real kick in the nuts, this card might change whose nuts get kicked;
This card might be the only thing that stands between Temporal Mastery and the ban hammer ^o^ Mana Leaking your opponent's turn 3 Temporal Mastery feels like getting a Time Walk yourself as your opponent would've almost tapped out, effectively skipping their own turn.
And if they don't tap out to cast their Temporal Mastery for fear of it getting countered? It'll be stranded in their hand (at least until turn 7). Can you imagine how fun the Delver mirror is going to be after Avacyn Restored? :D :D :D
Of course, Mana Leak doesn't completely neuter Temporal Mastery. It still adds a must-counter threat to any deck that can support it. For example in a planeswalker-control deck; the combination of the blue mythic sorcery and Liliana of the Veil already gives the deck potentially 8 must-counter threats on turn 3, which is not something a control deck (that I've recently played) has had access to *_*
A planeswalker-control deck is also the best deck for Temporal Mastery in my opinion because you can get double the usage of all your planeswalkers, which is already like casting extra spells every turn *_* Being a control deck also allows you to viably hardcast the blue mythic since you're aiming to get to the late game, netting an effect very similar to casting;
Having one or two planeswalkers in play gives you a lot of advantage, but you'll oftentimes still need a few more turns to truly push far out of your opponent's reach and bury them in card advantage. Temporal Mastery gives you those few more turns *_* It also helps 'ramp' you in the earlier turns too!
Which begs the question; how many Temporal Masteries should be put in the deck? I'm inclined to try 4 at first. It is THAT good ^_^ Especially in a planeswalker control deck poised to take full advantage of it. (which is considerably easy and requires little to no bending over backwards) You can even use Liliana to discard copies of the blue mythic that were stuck in your opening hand! :D
As you can tell, I'm really excited with the prospects that Temporal Mastery brings to planeswalker control decks. I really believe that it is the deck most poised to fully take advantage of the chase mythic, while other decks (like Delver Tempo) can only abuse parts of it and might under-perform despite people's high expectations :3
I do think that it is overhyped, though, and believe me, I tried really hard to think of the cons of the card.. but I only managed to figure out the cons of the Miracle mechanic itself (which Temporal Mastery kinda sidesteps :S) mainly because I hope that its price will drop so I can get my playset.. which judging by the way things are now, will take a miracle to accomplish :PÂ
I love playing Time Warp effects, you know what they say; "Time is a marvelous plaything" XD Seriously though, I really, really hope that Temporal Mastery won't end up getting banned.. Jace, the Mind Sculptor already tore a large hole in my pocket heart T__T
Anyway, thank you for taking the time to read such a long, long post ^^ it sure took me a whole playset of Temporal Masteries to finish it :P