Locations
Ah, PAX.
It signals the end of the Con season and the beginning of the new fall set rumor season. With this being Magic's 25th anniversary and the return to one of Magic's most beloved plane, we were sure to get WotC pulling out the stops to promote and celebrate their product like never before. After all, two years ago they rented an entire theater with constant drafts firing and events going on stage, held parades, hosted the World Championships, had a huge street wide banner welcoming everyone into the convention center and basically took over PAX.
Or they could cram 500+ people in a room and have a panel with a slideshow to introduce the new cards and call it a weekend.
You know, whichever one seems like the most sense for one of the most beloved brands of the genre.
Hey, at least they had a "Learn to play booth".
(Cut to: Title Sequence. Theme Music: "Where the Streets Have No Name" by U2 )
I could wax a long time about the misfires of WotC at PAX and what could be the cause of them, but we're here to talk about what was revealed at the PAX panel and how that works with Commander. I don't think I'm going to cover the previews each week but I'll have a complete look when the full list is out near the end of the month. What we can do now is talk about a bunch of big picture stuff.
New/Returning Mechanics
Selesnya
We'll kick things off with my favorite guild and one of my favorite mechanics. Selesnya's Convoke is the only returning mechanic in this set, but there is plenty you can do with it.
This wording is slightly different than when the mechanic was created (It doesn't actually reduce the cost of the spell), but the effect is still grand. With enough creatures on the battlefield, you can cast spells for free, which is the entire appeal of this mechanic. Used plenty of times before, a "cost reducing" mechanic can be dangerous if the cards are too powerful. Luckily, there's nothing in Commander that can be abused.
Top 5 Convoke Cards before Guilds of Ravnica:
Obelisk of Urd and Hour of Reckoning are great for when you're going wide and playing a ton of token creatures like elves or soldiers. Chief Engineer can slide into Blue/artifact heavy builds where it's just like Improvise/Affinity and can net you those explosive turns. The top two cards on the list are just plain busted and, ironically, don't need a ton of creatures to pull off (though they clearly help). Sprout Swarm can overtake games with plenty of triggers (Ivy Lane Denizen, and the combo loving Intruder Alarm). Chord of Calling is an instant speed creature tutor that puts its target on the battlefield. The number of cards in Magic that can do that at instant speed?
One.
We've seen three cards up to this point of the Selesnya guild watermark that work with Convoke. There's the buy a box promo Impervious Greatwurm which is a 16/16 Wurm and has Convoke and Indestructible for 10 mana. I'm always interested in Indestructible creatures, but it doesn't have trample or hexproof. I guess you can always give it trample. Conclave Tribunal brings us Banishing LIght with Convoke, so we know there's good bones there. We also get our first and only previewed Commander: Emmara, Soul of the Accord.
She's much better than the last time around. Not so fun fact: In Dragon's Maze, Emmara was supposed to have Voice of Resurgence's power, but it was a Mythic ability. The Maze Runners (other Legendary Creatures that were one of each guild), needed to be at Rare since Ral Zarek was already at Mythic and wasn't a Maze Runner. Emmara lost her awesome card text and had to be tied into creature tokens somehow. That's why the elemental token for Dragon's Maze is exactly like the one in the background of Emmara Tandris' art.
We'll get into Emmara once we know the full set, but I like the number of things we can run with her. Not only is she good with Convoke (and gives you more tokens to run with Convoke), there are a good number of cards you can use that can trigger her ability. Glare of Subdual, Vehicles, Loam Dryad, Hand of Justice, Throne of the God-Pharaoh, Quest for Renewal, Springleaf Drum, Honor-Worn Shaku, Paradise Mantle. Throw in a Paradox Engine and Skullclamp and baby you've got a stew going.
Boros
I, uh, well, let's just take a look at Mentor.
Mentor seems fine in Limited, but Commander is far from Limited. With this mechanic, you need at least two attacking creatures to make it work. Since it's in 
, there isn't too much evasion or cards with Infect that would make this at least a bit more interesting. The creature with Mentor should always been the one to be targeted for kill spells or bounce first and then you, the attacking player, will be left with a smaller attacking creature anyway. I'm sorry , but I don't think we're going to see many cards that work well with this mechanic in Commander, even if you add in Green for Doubling Season.
Golgari
Undergrowth is already going to have a spot in some established decks: Graveyard-based creature decks. WIth Meren, Savra, Kresh, Sek'Kuar, and Karador, as popular 
Commanders with a graveyard synergies, Undergrowth is poised for success provided we get some good options. The mechanic's effect is based upon how many creatures are in your graveyard, so in a larger deck you can get a larger effect. Look at the one known Undergrowth card at the moment.
It's almost like an early game Tragic Slip or a late game Tragic Slip. The bonus of exiling the creature when it dies makes the card much more powerful (since it says "if it would die this turn", feel free to use this as a combat trick or in combination with another pinging spell).
One of the most impressive things about this mechanic is the fact you don't have to use it in a graveyard based deck. Even though it would obviously shine in those type of builds, you're going to lose creatures during the natural attrition of the game. A card like Necrotic Wound could be Black's late game Swords to Plowshares. That ain't low praise.
In 's slice of the Color Pie, you might find Undergrowth to have the following effects with its variable size: Remove cards in a graveyard, make 1/1 Saprolings, gain life, drain life, put +1/+1 counters on creatures, tutor for a card with converted mana cost X, Draw cards and lose that much life, reanimate creatures, look at the top X cards of your library and grab something, mill that many cards, and a limited Duress based on the converted mana cost. The ability is wide open but its Commander viability is all going to depend on how the cards are costed. "Isn't that just, every card?" you might ask. Sure, but since we knows what it's based off of, it allows us to narrow down when we focused on graveyard based decks. This is the mechanic with the most to gain or lose.
Dimir
From one of the most variable to one of the most straightforward in terms of power. Surveil is a take on Scry, but with a twist.
(Note, this is only taken from Surveil 1 spell, at time of writing, we don't have the wording where X is more than 1.)
We've all had those Sensei's Divining Tops where we're looking at three cards and none of them are any good. Now, along with Scrying, we have another way to control our next draw. The "throw it into the graveyard" aspect of the card isn't a bug, it's a feature. People see the power of Search for Azcanta, and this is just the same ability only tacked on to other spells and effects. While it's like "Oh, that makes sense with Nacromoeba", it also makes sense to use a tutor to put something on the top of our library then Surveil it to put it in the graveyard. Suddenly we have another Entomb/Buried Alive.
Right now we've seen it on a discard spell and a counter spell, but there's plenty of uses for this keyword. I don't think we'll get another one like Search for Azacanta, but maybe you can tap a creature to Surveil or Surveil and draw a card (here's hoping for a "New Preordain/Ponder/Serum Visions). This can be good in Reanimator decks, but this is clearly a control mechanic. And we've been told that Surveil is variable as well, so it's not just Surveil 1, but it could be more. To dig down further in your deck and plan your next few is powerful.
Izzet
And the last mechanic might be the most fun. It's a combination of two mechanics, which itself is very Izzet.
What we have here is a combination of Flashback and Retrace. The ability to get multiple uses out of a card instantly causes me to take a another look at it. We've got one card currently and it's the most made up of words in the history of made up words.
Besides getting my Johnny senses tingling, we're also going to see this effect on a variety of cards. We're going to be able to treat it like Flashback and get more than one use of it. Even if it gets countered or milled away, it can be used in the graveyard.
The downside is we have to discard a card.
Again, it isn't a bug, it's a feature.
So we can use this with Madness (Hello Circular Logic and Welcome to the Fold), we can toss actual Flashback cards in the graveyard (Deep Analysis, Conflagrate, Faithless Looting, Past in Flames), we can use this for reaniamator in The Mimeoplasm, Muldrotha (Obviously the Mono-Blue cards) and Sedris. Body Double and Feldon, of the Third Path seem good with that huge creature discarded to do whatever last turn.
Ignoring the discard part of it for a second, the actual Flashback part of the keyword is just gravy. While you're not going to see many 
Commanders outside Mizzix take full advantage of it yet, the ability to do so makes it...
Wait, the mechanic totally works with Jori En, Ruin Diver. Gotta jump through that hoop to draw that card (writes the person with the Sygg, River Cutthroat deck).
The Shocklands
I'm glad they're back. We need them to be reprinted so often, though they only get reprinted on Ravnica for some odd reason. Your deck doesn't need the Shocklands unless it cares about basic land types on non-basic lands (Fetchlands) or you need a little more mana fixing. Don't go paying outrageous prices for those as they should go under $10 a piece for them in October. Get them when you get them but don't rush out and think you're going to miss out; this set will be opened a ton.
Mythic Edition
The last thing I want to talk about is this Mythic Edition that they're releasing. All we know, as of me writing this, is that it's going to be around $250 for 2/3rds of a box of Guilds of Ravnica but with 8 more packs each with an extended frames art Planeswalker. The bad news is that it's being sold on the Hasbro Toy Shop website, which means if you didn't like getting your SDCC Planeswalkers from there, you most likely won't like getting these from there as well.
Right now, we know seven of the eight Planeswalkers that will appear (Vraska is the eighth but her card hasn't been revealed yet). Daretti, Ingenious Iconoclast; Elspeth, Knight-Errant; Liliana, the Last Hope; Nicol Bolas, Planeswalker; Ral, Izzet Viceroy; Teferi, Hero of Dominaria; and Tezzeret, Agent of Bolas are the known Planeswalkers. The art looks great, but I'm not completely sold on the idea. That's a lot of money to throw at eight pretty looking Planeswalkers, especially if you don't use all of them in your Commander decks (at the moment, I only have Elspeth in a deck). This is something to keep your eye on if you love to completely customize your deck but this isn't going to be for everyone. Just understand that.
I want to say thanks to everyone I met at PAX and played some games with. I built a Canadian Highlander deck and played with a few other people and it was a weird experience. Casting Balance? Not having a Commander? Seeing Moxes (though proxied) on the other side of the battlefield? It was fun for a nice change of pace, but put me back in the format where I can pull Brion Stoutarm from my Commander Zone and tutor up Vicious Shadows (which happened this weekend and it was glorious).
Next week we're getting a break from previews so I'm going to take a look at the Standard legal cards that will be rotating and some ideas of what you might want to pick up for Commander, though not for financial speculation (not my forte). This is a normal thing that happens around this time of year: some people go back to school shopping, I go back to rotation shopping.
I swear that sounded cooler in my head.
