I see, I won't consider Dedede to have good neutral anymore for now then. Out of interest related to the topic though, who does everyone think of as the best characters in neutral, advantage and disadvantage respectively? I'll relist my top 5 neutrals with a bit more thought as well as the other two categories. Note that I'm not claiming anything with this, just bringing up some points and ideas.
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Neutral (efficiency at getting control of the match):
Mega Man is basically the only heavy zoner in the game with an actually good grab game. Villager has arguably the best neutral b in the game with pocket, obviously more useful in some match-ups than others although it's never useless as it grants a decent amount of invincibility. He also has 2 different projectiles that can travel on any level he wants, simultaneously, as well as a quick disjointed uair and dair. Diddy Kong demands a lot a caution from the opponent because of the follow-ups he can perform out of grabs which are easy to get being so fast with good range and bananas to help him out. Sonic forces a guessing game with his approaches and usually wins because of his speed. Sheik has the tools, mobility and the safe frame data to both force approaches and approach while also making sure the opponent is punished for making a mistake. If (or more like when) her chaingrab becomes a thing, you'll also have to treat Sheik like lesser ICs. I feel like Little Mac could go well in here, but don't have enough experience on him.
Advantage (efficiency at keeping control of the match):
These characters are hard to get off of yourself once they get in. They all have good throw and combo setups and can juggle other characters with ease, Ness a little bit less so, but he has PK thunder to reliably harass half the cast offstage and he's arguably the most efficient KOer in the game, even more so than Diddy Kong. The first four also have the highest overall mobility in the game, combining some of the fastest running speeds, falling and fast falling speeds and horizontal aerial speeds in the game. Sheik's and ZSS's frame datas combined with that are amazing for rushdown, while Fox's utilt and nair and Falcon's dash grab provide setups and resets that are sometimes hard to react to. Something Falcon also has that the others don't is a reliable spike in his dair for edgeguarding and the ability to take more risks due to his long survivability, although Ness' weight isn't shabby either. Mario and Luigi are also good with their combo game, but their overall mobility just isn't good enough, more so for Luigi.
Disadvantage (efficiency of stopping opponent's control)
None of these characters mind about being on the receiving end too much. While Villager can drop down to the bottom corner blastzone and still recover
to the opposite ledge of the stage, he doesn't have too many options to break out of combos with besides nair. He still makes it however, considering how good he does just camping around the ledge. Thank science this game doesn't have conventional ledge mechanics. Pikachu can escape horizontally with side b, stall under the stage with thunder and make it back to the stage fairly unpredictably with quick attack, as well as break out of combos with his fast aerials. Lucario, that is correct; this may seem like a silly logic but no matter how you look at it, being in disadvantage is necessary for Lucario to reach efficient strength, so he only really minds about it after around 100-120% depending on the match-up. Even at sufficient percents, while his recovery isn't as good as people think, it's among the better ones when used right and his aura b-reversals are defensively very useful. Yoshi can basically challenge anything with dair and eggs and use his super armor to nullify gimps offstage. Him and Jigglypuff also shake half the cast completely off of them with their aerial mobility and can break out of resets and setups with their quick aerials such as nairs. Shoutouts to jump Shulk though.
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If all the categories were top 10 instead of top 5, Sheik, Pikachu and Yoshi would be in all of them, as none of those characters have any considerable weaknesses. I think because of that it's very unlikely any of them will ever be unviable. Also if any character such as Rosalina is missing from any of the categories, it's because I don't have the knowledge to put them there.
Now, what is this kind of theorycraft good for? At the very least if we make this more comprehensive, it'd be easier to truly extract some clear pros and cons in characters and really think about what they're going to do for the character, and thus expect some characters to become more viable and others less viable in the future before the metagame actually concretely develops, and at the same time speed up its development. If the development of SDI and Snake's super exploitable recovery were given more thought early on in Brawl for example, it might've been easier to expect him to drop a few spots in viability before the metagame actually developed.
Moving on to Smash 4, I think that slow runners and characters with bad grab games for example just fundamentally won't do very well in the metagame unless those are for mandatory, compensating reasons such as extreme aerial mobility or a strong keep-away/camping game. This is because your only OoS option is often jab or grab, because of how effective shielding is and because of how important quick punishes are for keeping or getting the momentum in your favor. Slow but heavy hitters probably won't flourish either despite rage considering how ridiculously good some characters' frame data is while still having good damage and knockback properties in their moves. Similarly I could see rage's importance being emphasized and players capitalizing on staying alive as long as possible by playing more "lame" and minimizing any risk at high %s, making heavy but mobile characters more viable than they would otherwise be. Lastly, bad recovery isn't as bad is it was before because of the ledge mechanics. Maybe these points are obvious, but at the same time they shouldn't be overlooked because we're mostly focusing on short-term metagame.
It'd be interesting if we made long-term tier speculation with factors like these in mind. Good mobility and frame data will always be important, but at the same time I think difficulty KOing while getting yourself KOed quickly will be emphasized in this Smash, hence I think Diddy Kong may actually keep his throne, Yoshi will be top 5, and Sheik and Pikachu will stay within control despite their ridiculous potential.