Why is Sword of Body and Mind regarded as the weakest of the Swords?

Question

Sword of Body and Mind is part of a 5-card cycle:

• Sword of Body and Mind
• Sword of War and Peace
• Sword of Feast and Famine
• Sword of Fire and Ice
• Sword of Light and Shadow

All cards in this cycle have seen some amount of tournament play, but Sword of Body and Mind is generally regarded the weakest of the five, and is the least expensive in most stores.

Why is that? Sword of Body and Mind doesn't look any less powerful than the other swords, and it is the only one that directly improves your board position by making tokens.

Why is Sword of Body and Mind generally regarded as the weakest of the five swords? What advantages do the other swords provide that Sword of Body and Mind doesn't?

Answer 1

It's just not very good. Sword of Body and Mind's abilities aren't as powerful individually, and they have very poor synergy with each other.

Sword of Fire and Ice is great for a tempo deck beating down on another tempo deck:

• Draw a card: +1 card advantage.
• 2 damage to target creature: often +1 card advantage. Lots of creatures worth killing have 1 or 2 toughness (e.g. Dark Confidant, Mother of Runes). At worst, it speeds up the clock a little.
• Protection from red: negates red-base removal, which is plentiful because Lightning Bolt is SOOOO good.
• Protection from blue: very marginal, but means your opponent can't win tempo by bouncing your creature.

Sword of Light and Shadow is a great card for creature-based midrange:

• Return a card to your hand: consistently +1 card advantage in a deck with a reasonable number of creatures (16+).
• Protection from white and protection from black together in one card: negate almost all of the non-damage-based creature removal in the game. +2 toughness also helps make your creature resistant to red removal.
• Gain some life: marginal, but it can help one midrange creature deck beat another in a damage race.

Sword of Feast and Famine is superb in midrange control decks like Cawblade:

• Opponent discards: often +1 card advantage. You don't get this if your opponent's already running on empty, but if that's the case you've likely already got them on the ropes.
• Untap your lands: this is a massive strategic advantage. Very easy to keep up mana for counterspells or removal while still developing your board.
• Protection from black: negates a lot of removal.
• Protection from green: a lot of the biggest creatures are green, so it's nice to be able to slip past them. Thanks to the Sword's untap ability, you can easily attack with one dude and then move the Sword to another one so you'll have a pro-green creature to block your opponent's Tarmogoyf. The real value is that it's stapled to protection from black, though: you're giving your creature bonus toughness (to get it out of burn range) and making it immune to black's targeted removal and making it immune to damage from giant green creatures — sure to give Jund fits.

Sword of War and Peace is a massive clock swinger, useful to any reasonably fast deck:

• Damage your opponent a whole bunch if they're hoarding cards: basically makes your creature a very fast clock against control.
• Damage your opponent and gain life: creates significant life swings in an aggro/tempo damage race.
• Protection from red and protection from white: negates a lot of removal, including cheap removal all-stars like Lightning Bolt and Swords to Plowshares/Path to Exile. Pro white also lets you bypass token swarm defenses like Lingering Souls.

Sword of Body and Mind is, in contrast, a mishmash of abilities that aren't so great by themselves and don't really fit together:

• Make a token: technically +1 card advantage, but a Grizzly Bear is kind of a bad card. In most cases this is flat-out inferior to drawing a card, getting a creature back from your yard, or being able to blast something with a bit of damage (since you can remove weenie creatures with actual abilities).
• Protection from blue and from green: these are the two colors in the game with the least removal.
• Mill: meh. Mill's not always terrible, but here you only mill them when you are inflicting damage. In most cases, that's strictly inferior to any kind of effect that just lets you inflict more damage.

Answer 2

In short, because its protections and its effects are least relevant. Milling 10 cards from an opponent's library, while it will (usually) eventually lead to a game win, does nothing in and of itself; and putting an additional body into play means another creature to carry the sword, but is often seldom directly relevant. By contrast, Sword of War and Peace deals additional damage directly; Sword of Fire and Ice both deals additional damage (to a target of the attacker's choice) and draws a card; and Sword of Feast and Famine is disruptive with its discard and allows the attacker to cast spells pre-combat (during the Standard season that it dominated, for instance, a Squadron Hawk or Jace, the Mind Sculptor) and then still have their lands untapped to keep up counters on the opponent's turn.

Sword of Light and Shadow's effects are arguably worse than Sword of Body and Mind's; returning a creature to hand is arguably less useful than putting a small body into play (since mana still has to be spent on the creature) and the lifegain is as modest an effect as lifegain usually is. But this is where the other factor comes into play: both White and Black tend to have viable removal spells, on the order of Doom Blade or Oblivion Ring, and so protection from either or both makes a creature much more viable. All the other swords offer protection from either Red or Black, the classically removal-heavy colors; Sword of Body and Mind, on the other hand, only offers protection from Blue and Green, the two most removal-light colors. Bounce spells tend to be viable parts of a format only rarely, and while punching through Green monsters is often useful, SoFaF provides that same ability with better effects and a more relevant secondary protection.

Of course, all of this analysis can go out the window in other environments; in particular, Sword of Body and Mind is often regarded as the best sword for limited environments, and in particular in most cube-drafting environments. There, the mill becomes much more relevant (since often just two swings will be enough, and three virtually always will), the protections balance out somewhat, and the additional body is even more board-affecting.