I didn't play with everyone as I'm not a huge solo Smash player, it's a party game for me, but going on just general interest, this is how I'd rate them.
12. Byleth - Not a Fire Emblem fan at all, so all additions of this series has always been very underwhelming.
11. Hero - Another series I was never into, though I appreciate this one abit more than Fire Emblem for its history.
10. Pirahna Plant - It's a random and very goofy addition, but I think it's kinda fun to add an enemy from Mario that isn't your established boss characters and has an interesting moveset.
9. Min Min - I was more interested in seeing Twintelle show up over Min Min, because it was guaranteed this game would show up in Smash and is a fun addition.
8. Steve/Alex - While I think Minecraft is a very weird addition to the game, I understand why it is here, and they do have an interesting move set.
7. Joker - I may have dropped the game, but Persona 5 has a great style and look to it, so Joker makes a fun addition to the game.
6. Kazyua - This is where I think the additions start to get more meaningful in general, introducing a classic fighting game character alongside other ones so that you can have a game that has Street Fighter, Tekken, and King of Fighters all in one.
5. Terry - Same for Kazuya, I just find Terry a cooler character.
4. Sora - Sora was never a pick I really wanted, but is a really fun addition to the game.
3. Pyra/Mythra - I'm a big fan of the game and I thought they were made to show up in Smash, though not in the way I expected.
2. Sephiroth - I feel like we needed more villains to show up in the DLC, but Sephiroth is a huge get.
POWER GAP
1. Banjo-Kazooie - There has only one ever been one reveal that had me overwhelmed. Others were exciting and fun, but this was the one that I got emotional over, even as someone who doesn't play a lot of Smash. BK has mostly been ignored since Nuts & Bolts other than being on Rare Replay and tiny nods strewn about, so it gave me some hope that there is a future for the series again and it's lead to them putting Banjo-Kazooie into the Nintendo 64 selection coming to Switch and that makes me a very happy person.