This is a pretty good list generally.
IMO my two cents which no one asked for:
Overrated (one tier only): Wario, Zelda, Lucas. I agree w/ SB's assessment of Wario. Zelda and Lucas are still to be seen, but I'm not super impressed.
Underrated (also one tier only): Dedede, Snake, Marth. Everyone has always underrated these characters imo.
I'll just explain the two characters I know best (and I am biased because I mained both of them).
Dedede has an pretty good dash dance combined with the absolute best grab in the game (on multiple levels), insane vertical camping + spacing/walling game combined with a command grab mixup, a super underrated zoning projectile, an above average recovery (though punish game against his recovery is HARDLY optimized) AND top 5 edgeguards in the game. His big ol' hurtbox sucks, but we often rate on neutral and DDD actually has this super versatile and weird neutral that opens up a lot of characters in unexpected ways. Very few people understand him I think. He does have a few bad matchups but he goes even with TON of characters. I actually see him going even to positive with all of high tier except maybe Diddy Kong or TL. Everyone else in low mid is smartly placed - they lack in approach in some key way - but Dedede has way more tools than everybody else there.
Link is SUPER underrated. Even if he has some really **** matchups against spacies (and a questionable one against Falcon), his projectiles still gives a large section of the cast trouble in 3.5. He's also never really had elite class representation, even in 3.0. NickRiddle and Wolf were great and all, but idk, I still think he has a ways to go in terms of people fully using his kit.
I'd also switch DK and Ness, but that's just from seeing the struggle bus of Ness in 3.5, where he used to do better.
I'll go ahead and agree with my cousin on all accounts. And point out at Flex Zone, Aklo took out DJ Nintendo, The Moon, Envy, and Shiny Zubat with Link. He was double eliminated by Poob.
Also, Poob ran train on so many people, with several 0 to Kills on Professor Pro and StereoKIDD. DK has kill confirms out of grab on every cast member regardless of weight, and the ability to combo nearly everyone either through cargo uthrow dairs, or chained uairs and keeping them above him. His neutral game isn't great, but it isn't terribad either. He has good grab range and great pokes and range on his aerials, not to mention his jab-jab, is one of the best. For kills, he can reliably count on grabs to dk punch at really wide percent margins, uthrow uair on platformed stages like BF/FoD/YS, and he has up b OOS which is so strong. His main downside is his recovery sucks, but if we truly believe that at higher skills, punishgame/edgeguard game becomes optimized, then I'm not sure having a poor recovery is the worst thing if you have a punish game that reliably kills on all stages against all weight classes.
Also, cargo walk off is a pretty insane comeback mechanic when he needs it.
Meanwhile, for Ness, you can point out that StereoKIDD got 5th and went really far, going as far as to take out Seagull Joe. But I'd argue (and will keep arguing) that Ness truly is bottom tier. His neutral game is absolute garbage, and when people get the matchup experience they need, they won't get caught by fair into grab, or tomahawk grabs. Stereokidd got most of his kills and leads off of miss teched dairs into jab resets, which are insanely good at the current skill level people are playing at.
But if opponents know to expect the dair and meteor cancel, or techroll after getting hit by them, or buffer roll/getup attack after the jab reset, Ness's punish game falters SO quickly. His recovery is also mistakenly purported as being "top 5", and was done so even at Flexzone, alongside the commentator point that it has "like 20 frames of invincibility at the start", but this recovery is still mid tier at best. Its startup is extremely long, it has 6-8 frames of invincibility at the start (i forget which), which helps you punish a bad approach timing but doesn't do much beyond that, and it has 20 frames of lag hwen you land on the ground. 20 Frames is a LOT of lag...people always try to intercept pkt2, but you can just as easily just grab ledge, waveland on stage, and start charging a fsmash where you think Ness is going to land (or in fox's case, an usmash).
Ness is efficient for tacking on damage, and he has a good punish game when platforms are involved, but he is bonafide bad. Only player inexperience allows him to thrive and look like the monster he is. He also has major problems with a lot of cast members.
For example, Ness can punish fast fallers pretty well, but he sucks v. Floaties, failing to have any good kill leadins beyond a random DJC aerial in neutral (short range), or Usmash after 150%. Ness sucks v. high mobility characters that he cant run circles around. Ness sucks v. characters equipped with disjoints (all swords). Ness sucks v. Characters who can't be gimped easily. Ness sucks v. Characters who control space extremely well with projectiles. And he sucks v. characters with good OOS options (whether its a quick aerial or a grab).
If any opponent has a set of the above, it is usually a losing matchup for Ness. When you consider all of that, you begin to realize how he's definitely worse than some of your listed low tiers, including DK.
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