|Some of the cards which sparks debates|
Library of Alexandria and Mind Twist
I'm grouping these two together. If you're playing a control deck and your opponent starts with Library, you are very unlikely to win. If you're playing aggro or midrange, and your opponent starts with Mind Twist, you are very unlikely to win. Of course, an aggro deck will also have big problems with the Library, but can sometimes race it; and a control deck will have a real problem if Mind Twisted, but they can occasionally claw back the card loss. The arguments against the "unfairness" of the two cards are very similar in the end, but different types of players tend to focus on different cards. Whether any of these cards (or both) should be banned is a discussion that was very much alive even in the mid 90s. An interesting mail thread, with players like Roberth Hanh (of "Schools of Magic" fame) can be read here. To quote one player in the thread, "We're not winning games with Black Lotus and Moxes, we're winning them with Library of Alexandria and Mind Twist." In the end though, we really don't want to ban cards in this format, and have decided to keep both Mind Twist and Library restricted.
There have been some discussions about restricting Mishra's factory as well. It is clearly a staple card, and probably the best creature in the format, but it doesn't seem unfair or warping. I guess that Stone Rains, Ice Storms, Sinkholes and such could see more play. Even cards like Cyclopean Tomb, Fissure, Psychic Venom and Blight could probably be good choices against cards like Mishra and the Library if they become to much of a hassle.
On the plus side, Strip Mine is a good answer to Library, Mishra and Maze. On the minus side, every single deck would play 4, every deck would up it's land count to 28 to give them a chance against a double Strip Mine start, and players who can't afford artifact mana would have a much harder time getting to cast their spells. It would slow down both matches and tournaments, and the amount of games lost to both mana flood and mana screw would increase as well. It's a very annoying card to play against, and of course extremely powerful. Strip Mine stays restricted.
Last winter, this looked like a very good candidate, but with draw7-burn decks at both first and second place at n00bcon, this seems like the wrong time to let the Vise roam free as a 4-off. Black Vise was restricted in Type I after the printing of Prosperity in Visions, as Type I and Type II shared the same B/R-lists, and the deck was far too strong for Type II. After the lists were separated, Black Vise was unrestricted in Type I again. It is possible that this card is not too strong for this format. Still, a burn deck that casts Wheel or Twister and draws a pair of Black Vises before passing the turn, or just anyone casting a pair of Vises against you turn 1 when you're on the draw, would be completely back breaking. 4-off Black Vise makes fast mana, and power, much more important, which isn't something we really want to do. It's a close call, but for now we'll keep Black Vise on the restricted list. It is a good candidate to be unrestricted some time in the future though, and we'll keep a close eye on decks that can use or abuse it.
Many decks play the Vault to get explosive start, but I have a hard time seeing The Deck or any of the other top tier decks using more than 0-2. It appears good in some sort of Hurkyl's Recall Fireball combo deck though, and it also looks very good in budget monoblack. In monoblack it can increase the power of an early Mind Twist, cast an early disk, or consistently play Sengir Vampire turn two without power. Casual combo and powerless decks are both archetypes we don't mind giving an extra boost to though. It will be interesting to see if this will make an impact, so here goes. Mana Vault is unrestricted.
Mana Vault will be removed from the restricted list June 1st. Happy brewing!