Safari so goodie… I see improvement in the Oktagon card design and that pleases me.
With this being said, here are my constructive remarks regarding individual cards:
Goes well
Aryel: finally a card that allows stalling while dealing with the opponent. This can be useful in those situation where you need to destroy X or more opposing creatures, so you don’t want to win too fast.
Damping Sphere: With all the groaning and complaining about Gilded Lotus, I’m happy to see its opposition. It will definitely find its usage and be a fun “hate” card. The fact that it’s symmetric ensures its fairness. Nice design!
Fall of the Thran: Yummy! This will help deal with nasties like Sphinx’s Decree (though looks slightly overcosted at first glance). The effect doesn’t seem very “White” though, does it?
Fiery Intervention: Finally support removal that has alternative uses against a support-free opponent.
Grunn the Lonely King: Very fun and unique effect, while also easy to read and understand. I like it a lot!
Haphazard Bombardment: Extremely nice mythic that runs a repeated demolish effect. Definitely fun to use. It’s not clear to me if it destroys the gem or just removes 1 shield. If it removes the support it’s very nice, otherwise it’s going to be a niche card.
In Bolas’s Clutches: Another fun card. I like the idea of stealing a creature via a recurring support. Seems powerful with Nyx but since the support actually sticks around it would need to be destroyed as reinforced to keep the effect going. And the cost is also acceptable as it circumvents hexproof.
Jodah, Archmage Eternal: Very beautiful design. Looks fun for some sort of combo deck, though I admit I am a bit underwhelmed it only fixes the cost of cards in hand. Though I guess I am thinking here of something severely broken, so this approach is more balanced.
Lich’s Mastery: One of my favorite cards in the set. Although powerful, it can bite back especially since the support does not reinforce, but that’s the fun of black. You win some you lose some. I am curious if this deals damage even if River’s Rebuked.
Mishra’s Self Replicator: Although predictable, the implementation is excellently done in MTGPQ. This is the perfect example of a card transposed properly from paper magic.
Seal Away: Wow, double Suppression Bonds is fun. I’m curious, does the check for legendary creatures happen constantly, or it’s sufficient to have a legendary permanent when it enters the battlefield?
Serra Angel: Surprisingly powerful creature. I was definitely not expecting this. It will be a great tool for lower tier players. Woohoo!
Slinn Voda: This is going to be insane! Annoying for some, godsent for others, going tribal to make the sweeping effect unidirectional is definitely fun!
Teshar: Nice transposition, I like it. Will be interesting to see how people can abuse it. My guess is in some sort of Nahiri deck.
The Eldest Reborn: Powerful, accessible, not super oppressive. I like it!
Urza’s Ruinous Blast: Yummy, let’s see if this version of Hour of Revelation makes an impact. My guess is some Elspeth deck. Depends how many retroactive cards are made legendary.
Verdant Force: People have already noted this will nicely combine with the RIX dryad. Looking forward to fun decks in this direction.
Yawgmoth’s Vile Offering: THIS is a legendary spell I actually want to cast.
To improve
Blackblade Reforge: This is the perfect example of a paper magic card translated poorly. Lands are not something you see as ubiquitously in MTGPQ as they are very specific supports, not the foundation of casting spells. And combined with the prohibitive cost, I guarantee this will be a niche rare people will only use to “prove that it has some value”.
Cabal Stronghold: Firstly, why is this not black? Yes I know, paper magic lands are colorless. But in MTGPQ it’s not like it makes sense to be played by a non-black planeswalker. And the fact that it is not black means it cannot ramp on its own - which should kind of be the point of any land. I strongly recommend this being switched to black instead of colorless!
Secondly, this one looks slightly underwhelming, but it’s probably because it’s only an uncommon. Since it doesn’t take reinforcements into account, we can expect that it will need to rely on a support strategy… but oh wait, ramping there means you might end up popping your precious supports.
Deep Freeze: Now this is more related to how legendary is implemented right now, but does it mean that Deep Freezing a legendary creature removes its legendary status? That seems kind of awkward… Why not keep legendary as a card super type same to paper magic?
Divest: Let’s be politically correct and either phrase it as “his or her hand” or use the new paper terminology “their hand”.
Forebear’s Blade: Not sure why this is a mythic, as it doesn’t look extraordinarily powerful or do something out of the ordinary to justify the mythic status.
Gift of Growth: It’s not clear to me from the way it is worded. So it pumps a creature by +2/+2 and if you have 4 mana in hand it further pumps it by +4/+4? Or it’s irrespective of the mana in hand. Because if it will pump the creature fully anyway, just word this as “Give +6/+6” and “lose 4 mana”. 
Gilded Lotus: At first glance I am also unhappy to see the one newbie players friendly accesible card be handicapped, but with so many people complaining about it, I guess something had to be done. I just hope the support count is increased now. I also wouldn’t have touched the mana cost as handicapping the mana gains to only +1/+1/+1/+1/+1 seemed sufficient.
Goblin Chainwhirler: Another card that could have been fun but unfortunately is severely limited by its mana cost. 2 damage in MTGPQ is not that big of a deal.
Grow from the Ashes: Draining mana on a ramp spell is quite counterproductive and beats the purpose. This is an example of design where two conflicting effects limit a card.
Jaya’s Immolating Inferno: The card text made me grind my teeth in disapproval as such a long description indicates unecessary complexity. Just because something can be done doesn’t always mean you should. Could have just as well have dealt 10 damage to the opponent and the first two creatures. N.B.: What happens if the opponent doesn’t have two creatures? You can’t cast it? Looks super limiting!
Memorials: Highly overcosted for the limited effect. Rare lands nowadays need to stick to somewhere around 5 or 6 mana to make them feasible even for low mana gains planeswalkers.
Multani: Same issue as Blackblade Reforge. Lands are not that ubiquitous in MTGPQ.
Oath of Teferi: I fear for this card in legacy. It will nastily break the game into two when combo’d with Emrakul. If it returned the creature at the beginning of the next upkeep, people could still abuse ETB effects without going infinite instantly. The fact that it’s symmetric doesn’t help that much here.
Phyrexian Scriptures: See Divest.
Rescue: Really poor transposition of the card. The whole point of the paper magic card is that it helps “save” a creature thanks to the instant effect. Would’ve been nice if it were for instance a support that wrote “Whenever a creature you control becomes the target of a spell or ability your opponent controls, return that creature to your hand and it gains 8 mana”.
Settle the Score: I like this card is an uncommon, I don’t like the prohibitive cost. Removal is important in the game, so probably a cost of 9 or even 8 would be more appropriate.
Shalai: Would’ve really loved if this creature gave the player hexproof as well. (though I suppose that’s more difficult to implement)
Shanna: If this counted reinforcements I agree it could get bonkers, but being limited to up to a 5/5 it’s super meh! Maybe if it got +2/+2 I would say it could make a real impact. Or +3/+3 for each OTHER creature you control.
Sulfur Falls et. al: I was expecting much more from this cycle. The way it is written, it is occasional ramp that won’t actually help you when you’re in a pinch. It’s a “win more” card. The design has its merit, but balancing it out a bit better to actually see play wouldn’t hurt.
Tatyova: Lands again… boy oh boy, I doubt anyone will find any means of abusing this card in a serious competitive deck. It’s a 4/4 with a “sometimes”, quite underwhelming effect. Lowering the cost here could help of course.
Triumph of Gerrard: What happens if you have two creatures with the same power? The card does not say…
Wizard’s Lightning: Definitely not interesting. If it deals 6 damage like Exquisite Firecraft it would actually be playable, but 3 damage puts this into the “unplayable” bin.
