Ok. I see lots of problems with this one.
Luigi is no longer top three material.
Luigi has very little traction, so he slides all over the place. This means that he can't really punish anything out of shield. He has good combos, but after the nerf, he has no real kill confirms, except with Dthrow Up B, and only with bad DI at ~80%.
Yoshi has the frame data, the combos, and the kill setups, but no tournament results. Most of us put him near the top of B tier.
Zss is CLEARLY S tier material. High damage output, incredible frame data, and kill confirms on almost every character starting from as low as 20%, and a true 0-Death on fast fallers. Also, a godlike punish game.
Lucas, unfortunately, is not A tier. I'd put him somewhere as Low B, High C. This is because Lucas lacks approach options. He can keep the opponent out with PK Fire, because it autospaces very well, and he can control the stage, but he still can't get in. He is also gimped by Rosa and Villager, although to a lesser extent than Ness. He also has very few tourney results, other than PinkFresh at Xanadu's.
Lucario has difficulty killing, because of the Aura Mechanic, and his frame data. His smashes are some of the slowest, and at low percents can't really kill. At high percents, they kill very well, but even so he has nothing to combo into it. He USED to have Aurasphere-cancel Usmash, but because of the hitstun modifier on it to remove shield locks, Aurasphere no longer links consistently into Usmash. In addition, he can only kill well at high percents, where even the smallest mistake can get you killed, especially against characters with good kill confirms ie. Ryu, Ness, Zss, etc.
Mario is easily A tier. He has all the tools that he needs: Frame data, Mobility, Recovery, Combos.
He racks up damage really well, he has a projectile (Although it's not the best), he has a good recovery and a stalling tool for mixups, and he's fast.
Kirby has bad mobility, and terrible range, with no approach options. He lacks a solid neutral to set up for his good edgeguard/kill moves.
Ryu is A tier
Great damage racking ability
Great kill potential + Setups into kill moves
Fairly safe on shield with Bair + Good shield pressure in general (Sourspot Fair, Collarbone Breaker, Dthrow in doubles)
Good mobility (Air speed + FA)
Good Recovery (Good range, if a little obvious/telegraphed)
However, I feel that we just need to see more results from him.
Megaman has poor frame data, and mediocre combo game, along with situational approaches. He lacks a decent jab, a good "Getoffame", and is easily comboed due to his weight.
Link is WAY high, and Tink is a bit low.
Toon Link can do vvvvvvvvv , Link can't.
I think that Tink should be higher than C tier. He's definitely a top contender in mid tier: I'd say middle of B, perhaps below Lucas. This is because Tink has really good itemplay, and good zoning ability, as well as solid KO potential and good setups. Also, he converts really well off of Utilt and bomb.
Link has throw combos and more power in his kill moves, but that's about it. Switch Tink and Link's placements.
Roy is not better than Ike, switch their placements. Ike has good throw combos, a good jab, and immense killpower, as well as mobility. Roy has some throw combos and good mobility, but his recovery is worse than Ike's (Arugably), and his combos do less damage. Roy's throws don't set up for kills at higher percents, and don't combo at all past ~50%. Ike's do. Ike also has more range, and kills earlier, on top of having more survivability.
I don't know why Donkey Kong is so low. The Ding Dong really gives him good setups/KO potential, and he has massive grab range to boot. Put him in C tier
Peach has flaws, but is definitely not that low.
Peach has poor range and poor mobility. Her turnips are short ranged, and while she gets good combos out of Down throw, and she's got float dair for shield pokes/stabs, she can't get around fast enough, and too many characters outrange her.
I'd put Captain Falcon at the top(ish) of B.
Falcon gets shut down by a lot of the top tier characters, because he lacks a way to deal with projectiles, and his linear recovery. Most of the top tier characters are either effective edgeguarders or have projectiles.
Falcon also doesn't really have too many combos, even out of down throw. Almost NOTHING combos into knee, and is avoidable through proper DI. His Uair doesn't kill anymore, and can't deal with shields outside of his grab.
WFT is really, really low on your list.
WFT has had a lot of her problems fixed, including her grab. She has a decent neutral game, and can camp edge pretty hard. She has a lot of zoning tools, and utility in healing. She has pretty good killpower, augmented by deep breathing, and she has Ok frame data. Low C, High D tier character.
Bowser Junior and DHD are too low IMO, but I don't know much about them.
LITTLE MAC IS NOT THE WORST IN THE GAME. By far, not the worst.
That title goes to Jigglypuff. It's almost undeniable at this point that Jigglypuff is just poor in this game.
Finally, you put Pit above Dark Pit. I just had a huge discussion about this. Dusk Pit sums it up pretty well.
I agree with you here. Many Pit players tend to overestimate Pit's arrows, they are great projectile but not as great as many claim since they are just a low % projectile with a minimum knockback and no combo potential. They can gimp but that shouldn't happen very often outside of for glory (I have seen some though). Good nuisance off stage but that's pretty much it. I would say Dark Pit's arrows are better on stage thanks to their better damage, speed, knockback and the fact that he can shoot 2 consecutive arrows faster than Pit if they miss.
Dark Pit's side b indeed got a huge buff and it is his best kill move now (in terms of KO potential) KOing Mario on fd at respawn point with proper DI at 103% and at the very edge at 80% while Pit's KOs at 142%. Center stage it's about the same with both Pits.
They aren't different enough to justify a separate tier spot though. It all just comes down to preferences.
Better arrows on stage: Dark Pit
Better arrows off stage: Pit
Better side b: Dark Pit
Better f tilt: Pit
