Lucina was the strongest amiibo in the late Smash 4 amiibo metagame. While she hasn’t shown that same level of dominance in Ultimate, a handful of determined trainers are bent on proving her worth; as a result, Lucina has achieved consistently high tournament results that have reserved her place in the higher end of the tier list.
Falco wasn’t great in Smash 4 and was actually fairly underrepresented in tournament play. However, with the advent of Ultimate, Falco has found a viable niche in the form of Instadrop — and even without it, the character has finally achieved the representation it so sorely lacked. Falco has a lot of potential and the changes to amiibo AI have opened up a realm of possibility for him.
Little Mac is rather notorious within the community; in the previous title, he was the only character who was fully banned from competitive play. In the late Smash 4 amiibo metagame, he was allowed back in under heavy restrictions. Although Little Mac has been buffed in Super Smash Bros. Ultimate, he is not the powerful force he used to be.
In Super Smash Bros. 4, Kirby’s amiibo was rather average. Although Kirby possessed a powerful moveset with high utility, he was held back by short range and several AI flaws. In Super Smash Bros. Ultimate, amiibo AI was completely revamped. Fortunately for Kirby, this AI update corrected the flaws he suffered from in the previous title. He still isn’t perfect, but he’s been given a fresh coat of paint that makes him well worth training.
The transition from Super Smash Bros. 4 to Super Smash Bros. Ultimate changed a lot. Several top-tier characters in the previous title were nerfed, and as a result their tier placement in Ultimate is lower. Mii Gunner, however, is exactly the opposite: in Smash 4, she was below-average at best and low-tier at worst; in Ultimate, she is considered one of (if not the) best characters in the game and has taken the championship titles of many tournaments.