I’ll be honest, I am surprised we are returning to Arcavios so soon. The plane simply has no real depth to it - even if you count the surrounding areas, they did not have enough lore to fill a whole D&D book. Unlike Theros and Ravnica - where the D&D sourcebooks on the subject were cover to cover with rich information and lore from their respective planes, the Strixhaven book provided what little lore existed, and the rest of the book was various other non-lore mechanisms to pad out the page count.

That said, since they are going back, I hope the focus is on Kasmina - a particularly interesting and under-explored character. Her entire schtick was causing trauma to people in an attempt to orchestrate situations where their sparks ignite, trying to build an army of planeswalkers for some future threat.

That is a unique, interesting, and somewhat terrifying story to tell - and one that they have been reluctant to explore (I think that lore is in an art book somewhere - not really a primary lore delivery system). I am disappointed it did not get explored before they scaled back on planeswalkers - I hope it gets explored now, with her trying to figure out how to adjust her plans in the modern planeswalker era.

The Reserve List is not about power in the slightest - there happen to be some powerful cards on it, but that has more to do with bad game design and broken balancing in the early days of design.

Short form, the RL is about rarity - Magic was trying to do something new in creating the trading card genera. At the time, it was unclear if the game component or the collectable component would drive sales. There was no real analog for a game of this nature, but collectable baseball cards had been a thing for a hundred and thirty years at that point. The RL was created to cater to that creator market, essentially hedging their bets that the game might be less popular than the collection value. This was, in hindsight, kind of dumb and we are suffering for it today, but they were in a complete unknown situation and hindsight is 20/20.

Thunder Spirit is a rare card from Antiquities (a set covered by the RL) that had not been reprinted in a white-border set. That means it met the definition for the RL, and therefore was added. There is no other inquiry - nothing about power, nothing about how useful it would be to the game. It meets the set and rarity criteria and therefore is RL.

It is not an additional three mana though - it is three mana you were going to use anyway to play a creature that normally would provide limited immediate value, and suddenly has value you otherwise would not receive unlocked due to a keyword on a different creature and no additional effort.

Take your “additional 3 mana deserves an increase of 3 power” argument to its logical extreme - you are essentially arguing summoning sickness should go away entirely. After all, you are paying three mana for the creature, and thus, under your theory, you should get three power right away.

It would make Enlist too powerful on the curve. Imagine playing a Guardian of New Benalia, a 2/2 for 2. Without Enlist, on turn 3, a 2/2 would be swinging for 2 damage.

Now, let us imagine you drop a 3/3 for 3 on your next turn. Suddenly, that 2/2 for 2 is swinging as a 5/5 for 2, without requiring any other enablers (like haste). That is a massive increase in damage already built into the 2/2 - normally an increase like that would require additional investment beyond the card itself.

veritablecvn already provided you a link about Nadu, but I wanted to respond about Oko, Thief of Crowns as well.

Wizards was pretty open about what happened with Oko - essentially Wizards did playtest it, but were too much inside their headspace. The problematic ability - the +1, was designed to build up your own board by turning low-value food tokens into creatures. During playtesting, Wizards extensively used the ability for its intended purpose, and it was fine.

Except for one little problem - they were so focused on its intended purpose, they did not realize it also acted as a removal spell. That error was a bit silly, but silly in the kind of way that can sometimes happen when a group of people all look at something for too long, and all collectively get focused on what they think it says, instead of what it does.

DemonDragonJ - While both cards are interesting to discuss, please make a new thread on the topic rather than try to hijack an unrelated thread.

Sephara, Sky's Blade gives you some redundancy with your commander, and you very likely can cheat on her mana cost given your fliers.

There are a few more wraths you could add - Day of Judgment and Armageddon come to mind.

White struggles with card draw, so Esper Sentinel is a pretty solid choice.

Also, just a personal pet peeve, the title of your deck properly should be Revelation 16:16 - using the plural “Revelations” is a pretty common mistake.