This Tier List was made before the Mini BOX Leaks, and while we won't make predictive measures until the box is officially announced/released sometime later this week (in case Konami changes something), we will discuss the impact of the cards mentioned in said leaks.
Noble Knights stay as the only Tier 1 deck of the format. Instead of going on why it's the best deck for the fourth time, let us instead take a look at problems the new Mini Box is going to bring for the deck.
Let us start things of with the UR Loading... . This card prevents Noble Knights from being able to activate any GY effects. That includes Loading... , Loading... , the floating effects of both Loading... and Loading... , every Noble Arms Equip and last but not least Loading... . As such, once Abyss Dweller's effect resolves, one would need to have 2 Equips in the Hand in order to be able to end on a Rank 5 using Loading... or Merlin, while also making it harder to do the regular combo in general. Thankfully, one is able to chain the GY effect of Until Noble Arms are Needed Once Again to the activation of Abyss Dweller, since the effect only applies at the end of the chain. However, it still ultimately forces out the effect of the Trap which on its own is annoying. It allows the opponent to capitalize on the premise that one is able to deal with the monster before entering the Battle Phase or even just being able to prevent the opponent from summoning the Monster at the right time to stop the OTK. Don't forget that neither Xyz Monster will float, making OTKs against Noble Knights even easier. Abyss Dweller would also prevent Loading... re-Equip interaction which is the only interruption the engine has on the opponent's turn.
Loading... entering the ring also means that there is another negate aside from Loading... to worry about. This card is an upgrade to one of the cards that this deck already struggles with going second while also being able to deal with any other Monster Effect on the field. This includes the removal effects of the Xyz Monsters, Loading... and Loading... , making it harder for Noble Knights to out.
Overall, there are going to be a lot of new Extra Deck tools which pose various problems for the deck and it will be interesting to see if the deck is able to adapt or not.
It may surprise some people that we kept Blue-Eyes at Tier 2. While their representation even exceeds Noble Knights from time to time, we don't believe that it belongs at the same level as Noble Knights. In fact, Noble Knights' huge generic weakness gives backrow decks like Blue-Eyes enough room to play their game, as long as you win the coin flip going first. Otherwise, Blue-Eyes doesn't handle a Turn One setup from Noble Knights particularly well either. Against other backrow decks, it has some advantages like having backrow removal with Loading... , targeting protection with Loading... and even power plays in form of Loading... , Loading... and Loading... . With the upcoming Mini BOX, this deck may struggle against the new generic Rank Four Xyz Monsters like Loading... and Loading... , which I think will be great additions to any deck that has space for them.
Additionally, Blue-Eyes faces a lot problems with the increased representation of Thunder Dragon which is a bad matchup as long as Blue-Eyes doesn't open Loading... into Loading... to protect their own boards from being blown out blown out or Side Deck cards like Loading... . Thunder Dragon is often too fast for Blue-Eyes and can usually play through backrow and 3000 ATK beaters quite well.
Loading... becoming a staple in Desperado Main / Side Decks is also a huge problem, since it shuts down the Blue-Eyes strategy if it's on board Turn 1 and removal isn't drawn. Loading... is also seeing a lot more play even in the Main Deck.
Desperado stays in Tier 2 for the time being. Turns out Quarantine is ever-present both in and outside of Duel Links: you should keep yourself safe as much as you should keep your Loading... safe on the Field, as it prevents Blue-Eyes and Noble Knights from doing relevant plays. Aside from that it's just same old Desperado: flip some coins, Draw 2 with Loading... , etc.
In the last week we began to see Thunder Dragon become more relevant in the competitive scene. This deck has the ability to break oppponents' boards really easy thanks to Loading... , Loading... and Loading... . Thunder Dragon is a generally a lot more consistent than it has been prior, as they run a 20-22 card list with at least 7 starters. As with other decks, Thunder Dragon will also improve with the upcoming Mini BOX with the addition of Loading... and Loading... .