Last week we saw two new potential new competitors: the first being Shaddolls and the second being a new stall-oriented build of Shiranui. I think there is now enough of a visible discrepancy to differentiate a Tier 1 and a Tier 2, but the power differential isn't much/
Tier 1
Blue-Eyes is a simple yet powerful deck, able to go second against most boards and set-up a strong Turn 1. The deck struggles against backrow removal/protection (mostly Tech Genus running Loading... ) but we are not in a heavy backrow-hate meta at the moment so the deck takes advantage. Also, Blue-Eyes has no problem dealing with Loading... (as a Normal Summoned Blue-Eyes is more than capable of getting rid of it).
With this Tier List update Blue-Eyes has been moved up, and it's no surprise with it great representation in both Tournaments and the KC Cup. Loading... banishing backrow and then dodging disruption with its Effect or Loading... is too strong for a lot of decks to deal with right now.
Zombies are strong, being able to spam the board with Loading... and Loading... . The deck aims to take advantage of a meta not specifically hating against it (only really needing to worry about Loading... from Rank 8 decks) and using Loading... 's effect multiple times to play through disruption or set up a strong board.
Zombies also gets boosted to Tier 1, boasting arguably more representation than Blue-Eyes. The deck is easily able to play both handtraps and Loading... which gives it a good matchup into the rest of the meta. It's also quit a skil-intensive deck in my opinion, so players have to practice their play if they want to keep their timer above thirty seconds.
Tier 2
Zombies looked to be the strongest combo deck of the format before Shaddolls started to shake things up. Both decks set up hard-to-break boards going first while having strong pushes going second when able to favourably resolve their power spells (Loading... and Loading... respectively). The main thing that holds back Zombies from complete dominance is it's weakness to various floodgates, and while Shaddoll shares this weakness to Loading... specifically, it is not commonly included in current meta decks. As such, Shaddolls enter the meta as a top contender and may even evolve to be the deck to beat in the future.