My set review so far for modern:
Cards that will see play:
-Scattered Groves, Irrigated Farmland, Fetid Pools, Canyon Slough, Sheltered Thicket(Bicycle lands): Great in numerous strategies and if you are just flooding. Will see play in many midrange decks just for the cantrip ability, life from the loam decks, assault formation, etc. Amazing cards that may change many modern mana bases.
-Censor: This card is one of the best counterspells that we have gotten in awhile. Having the option of pitching this for only U means that this card is useful in every phase in the game. While paying 1U for a force spike isn't the greatest, the versatility of this card always having a use is. Being able to cycle this then get it back with snapcaster mage later sounds really good. It also helps blue players get to cryptic command mana. I expect this card to play a lot better than it reads in modern. It wouldn't surprise me if this becomes a staple in blue decks based on the power level.
-Curator of Mysteries: There is a lot to love about this card. 4/4 flyer for 4 mana is already a decent body but the ability to cycle this for only U is crazy. This enables: delve creatures, allows you to keep hands that were not good in the first place, feeds goyf, thins your deck, you can get this back with Liliana, the last hope/kolaghan's command in the late game for it to turn into a finisher, etc. For me this card reads as "Instant draw a card" for most of the game with the option of turning into a 4/4 beater in the late game. Plus the sphinx plays well with other cycling cards, plays into liliana of the veil very will when it's out, doesn't punish you for running a playset and it's not legendary. Sleeper card of the set in my opinion.
-Archfiend of Ifnir: Similar to the sphinx there is a lot to like about this card. The biggest thing to like about this card is that it already has a home in living end decks as a way for that deck to deal with lingering souls/other small creatures that chump block living end creatures. Cycling for 2 colorless is also nice because the archfiend doesn't ask you to commit to any color for living end. Solid new card for them.
Cards that might see play:
-Cryptic Serpent in Grixis decks looking for another beater. It's 6/5 body makes this attractive because he can trade/outrade many creatures in the format. Plus he only needs 5 instants/soceries in your graveyard to cost UU and he gets a discount for every instant/sorcery so it's not embarrassing to cast this for 1UU. Also makes me want to brew with bedlam reveler again. Likes faithless looting, censor, thought scour, izzet charm, Jace, vryn's prodigy,collective brutality, liliana of the veil and liliana, the last hope. I'm very excited for this card.
-As Foretold in UW decks with Restore balance/Ancestral vision. That deck will also need Flagstones of Trokair to recover from the restore balance. There is a lot to like about this deck but it needs tooling.
-Gideon of the Trials: One of the flashiest cards of the set that will do more in modern/eternal formats than in standard. His emblem can just hose specific strategies by itself, he is a 4/4 indestructible creature, and he can turn off damage from a permanent. There is a lot to like here but his 1WW casting cost does sting and there doesn't seem to be a deck that wants him right now. It's worth noting that he seems good in the As fortold deck that I talk about. He isn't insanely strong but his swiss army knife abilities are something to look out for.
-Drake Haven: One of the reasons to run a cycling heavy deck. Drake haven already has cards that it wants (Scattered Groves, Irrigated Farmland, Fetid Pools, Canyon Slough, Sheltered Thicket, Censor, Archfiend of Ifnir, Curator of Mysteries.) and we haven't even seen all the cycling cards yet. It may not get there because this is bad in multiplies, it needs mana to do anything, and it's slow. It does give living end decks an alternate wincon through graveyard hate which is why I think this might see play.
-Soul-Scar Mage: A very powerful ability but I'm not sure what deck wants this card. It's worth noting that this can swing into huge creatures and have lightning bolt as backup so it can either trade or deal damage. I don't know where this card fits in modern. Maybe the old UR prowess deck? Will this make lightning bolt great again?
Cards that are almost there but miss the mark:
-Glorybringer: Similar to Channeler Initiate, I predict this card to be a standard all star but it will be hard for this dragon to see play here. It faces stiff competition at the 5 spot as other dragons outclass it in skred/land destruction. The flame slash ability is nice but there are very few cards that untap creatures that see play in modern. Much less the decks that want this creature.
-Channeler Initiate: This card will probably be a staple in standard due to the versatility of being a birds of paradise/small beatstick. However in modern this creatures asks a lot in comparison to other creatures.
-failure/comply: I like the idea of making it so your opponent can't cast the same card for two turns but this feels slow. Weaker than reflector mage which doesn't really see play in modern.
-Manglehorn: Great sideboard hate cards and Chord of calling target but it's kinda slow to deal with affinity.
-Nissa, Steward of Elements: One of the most interesting planeswalker designs that we have seen yet. Sadly she can't protect herself and needs a lot of mana to do work which isn't where you want to be in this format.
-Liliana, Death's Majesty: while I like the design of this card I feel like she is a tad too slow for modern right now. Powerful abilities but she is embarrassing to cast in the face of Thragtusk, reality smasher, Elspeth, Sun's champion,ugin,the spirit dragon, karn liberated, Primeval titan, etc. I can see her being interesting as a grindy option in the esper goyos deck that casts ghost council/jace but that's it.
-Vizier of the Menagerie: There is a lot of power to be had here in terms of card advantage but I don't see what he does that tireless tracker/eternal witness/renegade rallier don't do for card advantage. To make matters worse he is not a hit for collected company decks. It's worth noting that he has great interactions with evoke creatures like mulldrifter.
-Rhonas, the Indomitable: Powerful effect but if you can use this card effectively then you are probably winning already. This is a win more card in many circumstances are modern is capable of putting out 5/5s for 3 mana already so why jump through hoops?
-Kefnet the Mindful: While paying 2U for a 5/5 indestructible flyer is a really good rate this card has many hurdles to get there. The biggest hurdle that sees a lot of play in modern is liliana of the veil as she will make this card feel real bad to play. To make matters harder for our bird friend discards spells are heavily played in death shadow decks/abzan/traditional jund which round out roughly 25% of the format. (Inquisition of Kozilek, thought seize, collective brutality.). Even if you some how get past all of that path to exile is still a heavily played card.
-Hazoret the Fervent: Probably the most playable of the gods that have been spoiled this far in modern as the Pervert can be top decked and deal 5 hasty damage to the face as an indestructible creature. It also doesn't ask a lot of the player as getting down to 1 card isn't tough with LOTV and brutality being in the format. Still 3R for this ability isn't a great rate and path to exile is heavily played in the format for the hoops that this card makes you jump through. Close but no cigar.
-Oketra the True: Cute in bw tokens build as it gets instantly activated off of casting spectral procession but this is probably worse than Sorin, solemn visitor or gideon, ally of zendikar.
-Honored Hydra: Paying 3G for a 6/6 trample is okay in modern but you can probably do better. Cute card.
-Combat Celebrant: Another infinite with Kiki-Jiki, Mirror Breaker but there is no reason in the world to play this over restoration angel, Village Bell-Ringer, pestermite, or deceiver exarch.
-Trueheart Duelist: Cute for value but it's not a good card.
-Dusk/Dawn: Cute in aristocrat decks but not playable because dawn doesn't reanimate.