My predictions for Fighter's Pass Vol. 2:
FP6: Min Min: This lady's the winner of the Party Crash Bash last year, and is Yabuki's favorite character. Min Min as a new fighter would break the barriers about Spirits deconfirming and shoot up support for characters that have appeared in the Spirit Board like Akira from Astral Chain, Leon from RE, the Ring Fit Trainee from RFA, and a whole lot more.
FP7: Doom Slayer: This guy has had some strong support even after that interview a couple months back, and despite how long it's been since then, the CacoMallow leak STILL hasn't been proven fake. Doom Slayer has just as much going for him as he does against him, if not more.
FP8: Geno: Alongside the Doom Slayer, Geno has been the character that people think of when they saw the CacoMallow leak. Geno is in a similar situation to Banjo and Kazooie: making a debut as a Nintendo character, but rarely ever making an appearance as a character on Nintendo ever again because of Square-Enix, much like Banjo and Kazooie with Microsoft. I know Geno has been one of the #1 characters for support alongside Ridley, K. Rool and Banjo, so adding Geno would make more people extremely happy. I know a few people (And even subscribed to a guy on YouTube) that really want Geno in Smash.
FP9: Reimu Hakurei: The shoot-'em-up genre has been what's inspired Sakurai to make games, and Touhou is a game in that genre. Also, ZUN has been famously flexible in terms of copyrights of Touhou, just look at all the fan games that were made! Reimu would also be an indie game character, the first to be playable as not a Mii Costume (Sans, Cuphead).
FP10: Xenoblade character: Whether it's Rex & Pyra or Elma, Xenoblade has, admittedly, the short end of the stick when it comes to 1st-party support. Whether we get a unique Blade & Driver character with the former or a weapon-swapping character with the latter, it would be nice to see more Xenoblade characters in Smash, and if FP6 does turn out to be Min Min, that makes it all the better.
FP11: Iwata tribute: Going off some speculation going around, but capping it off with a tribute to the late Iwata would extremely nice and heartwarming. Whether it's Lolo, a golfer from the NES game, Balloon Fighter or Mach Rider is up in the air, but whoever that is, I'd be up for that, especially considering Smash Ultimate was Iwata's last request to Sakurai before passing.
As far as smash goes, it's the netcode itself. It needs a massive overhaul as it's been mroe or less using modified code from the brawl era iirc. And it's also flawed in its overall design.
a new server system alone won't help when each game itself likely needs a massive overhaul to it's matchmaking, netcode, etc. Nintendo's core design philosophy with their online service is outdated, not just their server system.