Let's get into it.

Arashin Foremost

WOW. This is seriously cool. This will remind everyone of Silverblade Paladin and that was a very good card. This is a little narrower and accordingly, its price will be limited. Silverblade was also a promo which limited its upside, but I still think this will be cheaper. Still, this is a $2 preorder. Cards don't really preorder cheaper than that. Do you have any confidence in a Warriors deck? These could get more expensive than $2. I think being relegated to a Warrior deck is a big liability, but $2 is an attractive buy-in if you are feeling saucy and think this could help Warriors get there.

Den Protector

It's no Eternal Witness, but in some situations, that's a good thing. I've seen EDH players say that they prefer this to EW in decks like Karador. In Standard, we don't have to pick between the two because this is what we get. Eternal Witness was a very good card and this does a good approximation of that, and has an additional, combat-relevant ability which could be a real dirty ability if you can boost its power with something like Become Immense. At a $3 preorder, this is pretty attractive, but only to save money later. I don't know that this will go high enough that you will be making a ton of profit selling these after a $3 buyin. It's a cool card, but it's hard to know if this will get there. Maybe pair this with Arashin Foremost and go to town with an unblockable double-striker.

Assault of Dragons

Target any number of creatures. For each creature targeted this way, destroy it. Its controller puts a 4/4 red dragon token with flying onto the battlefield.

This is pretty saucy. You can either kill one of their huge creatures whose abilities are giving you trouble, or you can turn Hordeling Outburst tokens into a swarm of dargons. Or both. There is real utility here, but it's also a 6 mana spell. This seems more cute than good. I don't know what the preorder price on this is, but I imagine it's too much. This is likely a very inexpensive mythic unless people really want a 6 mana curve-topper in tokens, something that current token builds don't really indicate.

Blood Chin Fanatic

Creature - Orc Warrior
1B, Sacrifice another warrior creature: Target player loses X life and you gain X life, where X is the sacrificed creature's power.

Orc?

OK, that aside, this card is really hard to evaluate, as are most of the warriors. Even a good warriors deck emerges and all of a sudden these are all $5-$8 cards if they are a 4-of in the deck, or they stay a few bucks because they're rares and are fringe playable but not real players. Cards like Gravecrawler were a few dollars on preorder but when the zombies deck made itself apparent with the full set spoiled, 'Crawler became $10. People are already playing BW warriors to modest success so there is a deck ready to take these cards, and this is a 3/3 for 3 with a very good ability to help turn extra, unneeded mana into reach and turn off their removal to an extent.

Will warriors be a real deck? I'd sleeve one up with proxies of the new cards and see if you start crushing. These warriors are all very cheap and could more than double in price if the deck is tier 1.5 or better so try and get ahead of the spike if it's coming.

Shorecrasher Elemental

Morphling? Could be!

Here's the thing - I think Aetherling was a better Morphling. Triple blue is brutal if you want this in a three color deck, and this is vulnerable until you pay 5 mana to flip it up so you can flash it out again. Base 4/4 after you morph it doesn't seem worth it. You don't have to pay the triple blue if you morph it, but that makes it vulnerable unless you have the 6 mana to flip it up and save it. All in all, you can't be as cavalier with this as you could with Morphling and I think the comparison everyone is making is probably a poor one. SCG sold out of this at $8 immediately, which means that a lot of people are drinking shorecrasher's Kool-Aid. This may be good, but it's not going to go in the Morphling slot the way Aetherling did. Aetherling, by the way, had little price upside due to only being played as a 1-of in control. I don't think this is good enough at dodging removal to be played as a 1-of which gives it potential upside and its mythic status really helps the price if this gets played. Do you want to buy in over $10? Is blue-heavy aggro going to be a thing? Aetherling this is not, and I think a little playtesting will bear that out.

The one thing in its favor is that this gives you a LOT of devotion to blue on its own and pairing it with Master of Waves could be spicy. Here's what the spikes on reddit are saying about the card. Read everything they say through "Magic Christmasland" tinted goggles.

Silumgar's Command

This is the control command. Ojutai's Command is cool and all, but that one is better suited to triggering Prowess than controling the board. Counterspell and removal in a single card, the 5 mana cost makes it hard to keep up, but even if they know you have it, it's difficult for them to play around. The brutality of bouncing a big creature or killing a small one while you also nuke a planeswalker is devastating. Not every deck plays planeswalkers and you may find yourself killing a small creature and bouncing another fairly often, but being able to bounce anything, including another planeswalker or a card like Whip of Erebos gives the card real upside. Still... 5 mana HURTS.

5 mana counterspells are historically clunky if you can't cast them for 0 mana, so this will be very interesting to see if it can crack the control player's 75. This is sold out at $3, but that can indicate a misunderstanding of the card's nature as much as it can indicate actual confidence in the card. I think Ojutai's Command is more likely to impact Standard, but people are certainly going to want to try this.

Notably, the spikes on reddit have the same "This is really clunky; how would you play it?" opinion I seem to.

Dragonlord Atarka

This is worse than the other Atarka is in EDH. GR ramp may want one or two of these in Standard if that deck ends up even being a thing, but I really don't like this as a commander as much as I do Atarka, World Render. This kills in 3 hits, but the other one kills in 2 hits. This is a better standalone creature and it likely gets played in the 100 if the other Atarka is your general, but giving other dragons abilities is what a commander is all about if you're playing tribal. This is really disappointing. If it dealt 5 when it attacked also, the card would be formidable and maybe even good enough to try in Standard. As it is, I'm let down. 7 mana isn't insurmountable and getting upside even if they kill it before it attacks is good, but I feel like this is less exciting than the other Atarka, though it will initially be worth more being a mythic. At $10 preorder, I'm not excited.