I currently think
Sheik:
Needles - something
Proportion kill power back to moves based on how much you make needles not stupid
ZSS
1% of flip jump kick (imo should suffice a lot, MAYBE DONT DO IT AT ALL HA HA), make jab and fsmash not whiff half the cast standing; thanks. NickRiddle-senpai mentioned something like 'up-b auto link for noticeably weaker would be best', and I agree, I care less about killing fatties with it for free at stupid percents and more about sheik and rosa not always falling out of it
(although it can be skilfully avoided I DONT WANT TO THINK, GOSH, no one who doesn't main a character understands how much we don't want to think about things, easy easy only please)
Ness
1% off Nair/Uair, growth off back throw. Buff as many of his pokes as you want so he can compete with sheik/rosa because he's no longer silly.
Luigi
Kill him, he's basically a bad guy, and just like all the other bad guys in this game (Bowser, Dedede, Mewtwo, Shulk [spoilers], Ganondorf, maybe Junior) should be low tier by default.
Or make dash grab have a lot more cool down. Maybe a dthrow adjustment but probably not necessary; make this **** take something fair for whiffing grab (Palutena does!). Diddy's nerf in his three are really hard for me to notice to be honest, so I think a similar frame or slightly worse would be acceptable.
Luigi hasn't really shown to have any unwinnable match ups yet though, if Sheik/ZSS get tapped down in potency then who's he losing to that isn't almost niche character level at this point?)
Mario
Hard to really justify much, but I'd love 1% off Up Smash. Nothing else is really stupid, he's got a well utilized kit. Probably deserves something in return... on his pokes? People are putting this character as high as top 5. We've heard anecdotes of Japan thinking he's the best in the game...
Is Fox a problem right now? Soso... Enough weaknesses (light, average recovery, easy to combo). The moment Luigi dies is perhaps the moment we start calling for Fox nerfs. IF I was going to think of anything it would be maybe a little KB off Up Smash (something that's as fast as it is and gets combo'd into reliably). With Luigi culling in mind, Fox would be an easy top 3 for me though.
Falco
Do what they did to Fox last patch, basically, I know they want to/have to.
Pikachu
still actually sucks, probably should get buffs for Pete's sake. Honestly he has enough of a weakness in lacking any long range 'poke' and this accentuates his poor range issues. He has down tilt. Sheik has fair/bair/nair act as one, Diddy has fair/bair, etc etc.
ESAM is just that good. Also I'll take this opportunity to say NAIRO IS JUST THAT GOOD,
and maybe zero suit should get buffs instead too~ :3
Diddy / Sonic / Wario
No one is really complaining about them at this stage in the West. Many agree Sonic is a mess though (and partially problematic) that perhaps because of japanese opinion has been relegated to the back of our minds as he continually become less and less of an issue; not because they fix him, but because they force him into a 1-way victory condition that only certain players could be successful with.
Ryu
DANGER ZONE. EVERYONE IN JAPAN PLAYS RYU ON WIFI. EVERYONE ON WIFI IN JAPAN WHO PLAYS RYU IS THE MOST ZONIEST NEUTRALEST CAMPIEST SHORYUKENOUTOFSOMETHING character ever (it's lame on wifi but it's really pretty to watch and fun to play around). It's almost like what Luigi should be. Except on a much much more higher depth character who's strong. I could see something happening.
He is Snake 2.0 in a lot of ways
Ryu has a
1.8x modifier on a lot of his moves. His entire moveset's safety got significantly buffed. This character can almost certainly be a demon (and definitely wasn't last patch).
And everyone else deserves buffs. But only Blue Haired Fire Emblem are going to get them.
HAAH.
(Forgive my blatant facetiousness this one time)