For those of you who have been away from the amiibo scene for a while, since Ultimate’s release it’s been well established that Bowser is the dominant force in the vanilla amiibo scene. He only has a few bad matchups (King K. Rool being his toughest), and his AI is so well programmed that it’s almost impossible to screw up. (Somehow, I still did.)
This makes perfect sense: Bowser has two moves that make use of corner cases in amiibo AI. His side special is a command grab that was also dominant in Smash 4. Amiibo don’t recognize command grab hitboxes, so they don’t properly dodge or block them. This is a huge benefit to the few characters that have them, such as Bowser, Ridley, Incineroar and Isabelle. You’ll notice three of those four are top-tier. In addition, his down special is a shield-breaking move, if each hit lands. This wouldn’t be a problem for normal players who can just roll away, but amiibo don’t always escape. Instead, they’ll try to shield or parry the move, which leaves them vulnerable either way.
In addition to his excellent AI and moveset, Bowser checks the rest of the boxes as to what defines a good amiibo. He’s heavy, hits like a truck, and has a useful recovery that isn’t easily gimpable by amiibo opponents. In human play Bowser is a nobody, but when amiibo AI limitations are introduced, he’s the obvious choice to wreck an opponent.
This isn’t all theory, either. Leaf was digging through some stats the other day and gave us all this nugget of information.

Up to this point, the community has not felt the need to ban Bowser. While there are many reasons this may be the case, I think it’s simply because nobody submits him to tournaments often enough for him to be a nuisance. Fortunately, as Leaf indicated above, Bowser is still overwhelmingly powerful in the amiibo scene and has a clear advantage over any other choice.
There are some murmurs that the newly-released Incineroar may be a counter to Bowser. That seems to be a logical choice: Incineroar also has a command grab that extends even farther than Bowser’s, and can KO easier. His Revenge, if properly used, can turn one of Bowser’s attacks against itself and KO the Koopa King with a single hit. He’s even in possession of one of the most powerful KO throws in the game. While Incineroar is certainly limited by his recovery, the sheer intelligence of his AI paints a bright future for this amiibo.
Ultimately, I support the Bowser ban, and the tournament I’m hosting tomorrow (Amiibo-Rawl) is the first tournament to uphold the ban after its introduction. We’re sitting at 18 entrants thus far, which sounds like we’ll have a shot at seeing what the meta is like when Bowser’s not around. That sounds delicious, frankly. I’ve heard it said before that many lower tiers are viable without Bowser’s presence, and I look forward to seeing that possibility develop, both in Amiibo-Rawl and in future tournaments.