Fine (for now at least):

Fox - I can't think of anything that needs to be changed about the spacies. They can be the absolute best, but only if you have high technical skill. That seems like the perfect goal

Falco

Wolf

Mario - P:M did the plumber some justice. My new favorite character

Diddy Kong - solid just like Brawl

Marth - Not as good overall, because others are better, but still a force to be reckoned with

Peach - It's a shame that Armada has moved to the Pit side, but White Peach at Xanadu...wow

Lucas - The "new spacie" in my opinion

Link - Has all the tools to win

Mewtwo - Gold-armor costume, omnidirectional float, tail juggling, 'nuff said

R.O.B. - The game's only air dash is pretty freaking awesome

Roy - Still the slower stronger counterpart to Marth, but actually usable now

Ike - Even slower, even stronger, but Quick Draw shenanigans and some easy kill combos make him pretty good

Sonic - And people thought Captain Falcon was reckless...haven't seen much use since 2.6 changes, so maybe some of those need to come back? I don't know, I wasn't around for Sonic 2.5

Yoshi - Still don't get the "Yoshi is God Tier" hype, but he seems just fine to me

Ivysaur - Lost use after nerfs in 3.0, but still viable I think

Charizard - Solid character, decent use, should increase with time

Squirtle - He's last on my tier list, but I don't know what to do with him that doesn't make him OP

Wario - Very solid, like a heavy character with Jiggz's air mobility

ZSS - Fast, okay kill power, great combos

Pikachu - seems fine to me

Ganondorf - Is it just me, or does he seem like a bigger target than in Melee? Maybe it's just me...
Time:

Snake - We need more Rolexs, more intelligent devoted Snake players. Imo, Snake is one of the best, if used properly

Sheik - Sheik has to adapt, especially with d-throw and b-throw changes

Pit - After Armada's Apex showing, it won't be long before everyone (*cough*meToo*cough*) plays him

Ice Climbers - once again, just needs some time to adapt

Kirby - If Kirby is REALLY top tier, I have yet to see it. I've seen some good Kirbys though, so we'll have to see if he needs buffs/nerfs

Captain Falcon - Need more devoted Falcons

Jigglypuff - Jiggz struggles in P:M, I find. Not sure what would need to be done. Maybe she needs a Hungrybox-esque innovator

Samus - Samus has some of the coolest changes (with her fire/ice taunt change), so I'd love to see more people pick her up

King DeDeDe - Much better than people give him credit for

Lucario - radically different play style than anyone else, so it'll take time before we have someone truly master him

Luigi - <3 Where is the love?
Buff:

Bowser - Bring 2.6 Bowser back! He wasn't OP, he was just new. No one knew what to do. He just needed time.

Donkey Kong - I think his moves need to be just 1 or 2 frames faster. It's so hard to do things with him because of the high startup lag

Olimar - He needs another Pikmin, that's all. 5 is the right number

Toon Link - He's like a weird combination of Toon Link, Young Link, and 64 Link. PMBR should try to stick to one of these (preferably not 64 Link)

Zelda - More aerial mobility and a better jump, that is all that is needed. She is very good defensively, but she doesn't have the tools to MAKE people approach. Melee Jiggz could bait with aerial pokes. Zelda has...Din's Fire?

Mr. Game and Watch - I think his hitboxes need to last a bit longer. He supposed to be a weird character, and I don't think he's weird enough. I also think his up air could be a bit stronger

Ness - They made the right buffs, but not quite enough. PKT2 needs to go even farther, and the yo-yo needs to be even stronger (both up-smash and d-smash)
Nerf:

Meta Knight - I don't have anything specific, but I have him on close watch