As for my general disclaimer: "This is not a ‘what I want’ list. This is not a ‘what will perfectly balance the format’ list. This list is derived based off expectations of the Konami thought process." If I stray from that anywhere, sorry! I'm trying to be as objective as possible here.
-Card Destruction has always been a problematic card. Not that in and of itself it's worthwhile at all, but that in certain strategies it becomes entirely one sided, and unhealthy to the gamestate. This card has been on many peoples watch list for quite some time now due to Dark Worlds and other degenerate strategies, but with the ever prevalent Dragon Rulers dominating the current game, advancing themselves through the use of this massive reload, it may well be time to finally put the nail in the coffin.
-The availability 3.5 big name decks have to #11 Big Eye (Dragon Rulers, Priestess Prophecy, Mermail, & Machina) on the surface is a balancing factor for the card. In reality, it creates Big Eye wars for the likes of which are extremely unhealthy for the game. With only 1 available copy, when to play your Big Eye would become extremely crucial. Potentially, it becomes whoever plays Big Eye first, looses. This mind set will also help to curb abuse of this walking (rather, floating) Change of Heart.
-One thing some people have noticed that while probably half of all other players fail to realize, is that while Spellbook of Judgment is arguably one of the greatest card ever printed, Spellbook of Fate is the decks win condition. Take Fate out of the equation, and Spellbooks are not really a very viable deck. However, to make this an effective hit, it must go to 1. Most people play 2 as is, so a semi-limit wouldn't change anything. With Tower to recycle, and Judgment/Secrets(Master)/Power to search, Fate is easily accessible as is. Limited to 1, the Spellbook player is forced to dedicate more time to fetching and recycling Fate, which in its own way halts whatever else the player is hoping to accomplish without annihilating the way the deck works.
-Similar to the unhealthiness created by the presence of multiple Big Eye, the ability to burn through an entire hand and replace most or all of it at will should be the definition of 'overpowered'. Rejuvenation, at minimum, is a Pot of Greed. Doing so multiple times furthermore becomes the games working definition of 'broke' unlike anything else.
-With the addition of Tidal, Dragon Ruler of Waterfalls, the Mermail/Water deck has gained a new powerhouse for abusing the ever-present Atlantean effects. In a potentially slower format with a few options taken away from the Top 2, the Mermail deck shouldn't have an open gateway to dominance again. There's not much that can be done to prevent that, but limiting their Stratos, which is already multiple times more effective than Stratos ever was, is the best way to attempt to do this.
-Spellbook of Judgment… what a card. Name one other card that does even half of what this does for any archetype in the game. Can you do it? Unless you're thinking Painful Choice in Dark World, I don't think you can even come close. However, as I spoke of above, the true power of the Spellbook deck is Fate. Judgment is an enabler, not a finisher. Spellbooks maintain advantage by overwhelming options, but even now don't retain the title of #1. With a bomb like this, they should have no issues dealing with everything possible, however this is proven to not be the case when compared to Dragon Rulers. Adjustments to decks like these rarely happen all at once, but come in phases. For now, force the deck to have to search the turn1 Judgment more often, bind that with a single copy of Fate, and deck should maintain stability moving into the new format without completely neutering it.
-The draw power retained by Dragon Rulers even with the limiting of Super Rejuvenation will still be staggering compared to anything other than Spellbook of Judgment. With the lack of copies of Rejuvenation, players will probably opt to add the 3rd copy of Sword that is currently not seen every often. If we want to actually halt the reloading the deck abuses so much, readily available replacements shouldn't be so easily found.
-Finally, Book of Moon. It's been said for quite some time now that a diverse and balanced game will always be the end goal, however we rarely see this. Book is one of those cards that allows less popular decks to better be able to break the progressions of more explosive builds, and be both offensive and defensive. There's not much more that can be said about this.
-With the upcoming release of JOTL and a resurgence of Synchro type monsters, it only makes sense to see a comeback of 1 of the 2 of the better tuners [that aren't Glow-up Bulb] in recent history [the other being T.G. Striker]. However, that same history shows us what can happen when these 2 work together [Trishula, but I'll get to that in a moment], which is why it would only be one. In a slightly slower format, Agents may have the potential to make an impact again. This makes Earth a better pick than Striker.
-Compared to the top2 of the current game, Royal Tribute is only 25% effective. It doesn't hurt Spellbooks, and it only cuts Dragon Rulers options in half. Many other major decks at the moment can mitigate the losses of an early Tribute by use of monsters like Constellar Sombres, Evilswarm Kerykeion, or Brotherhood of the Fire Fist - Spirit. Rogue decks like Madolche can activate Chateau, Dark World… will be Dark World, or Hero players can play Miracle Fusion if their able to remove Necrovalley. Gravekeepers could be a worthwhile rogue choice with this addition (and Book of Moon helps too).
While I don't propose that either of these will actually happen, it isn't out of all realms of possibility.
Trishula, Dragon of the Ice Barrier
-Again with the resurgence of Synchro support, 1 of the 4 may very well return. Brionac loops will never exist again, so that’s out, and Dark Strike Fighter OTKs fall under the same mindset. We already had the Goyo Guardian hype going into the current format, so I don't expect to see that happen; besides, I feel like only Zombies and 3Axis could readily use him anyways. OCG already has (and we are getting) Vulcan the Divine, so there isn't a big need for an unspecific 6. That only leaves 1…
-What does Imperial Order hurt? Spellbooks, and somewhat 3Axis. Otherwise it's almost equally bad against everything else. At most, the lone copy of Imperial Order would make it to the side deck, and there are 3 copies of Dust Tornado, and 4axis support in the form of Gorilla to take care of it. In this day and age, I don't see Imperial Order causing much of any havoc. Let's see where it takes us.
In the spirit of balancing the game, there a few choices I would make that give support to decks that are all but otherwise dead. I don't think much of any harm could come from giving players of those decks a format to enjoy. I'm not going to go in depth about any of this, as it shouldn't be needed.
Thunder King Rai-oh
That should cover it for this season. Right now we can only speculate, so let’s wait and see where the game really goes on September 1st. Play hard, and I’ll see you all again this time 6 months from now!