When talking about character design, there's so many factors to take into account. The usual is concept and execution. Still got to add in stuff like the game itself. A character can have bad concept, but be well-executed like Jigglypuff and Pichu, the joke characters. At the same time, a character can have good concept, but poor execution like most of the heavyweights not being strong enough in raw power in previous games.
When I think of "bad design", I think of really poor decisions and only one character comes to mind because of his conceptually broken tools throughout Smash: Falco. Others might say characters like Brawl Meta Knight or Smash 4 Little Mac and Lucario, but I'd say their designs are fine, but they were executed poorly, especially Brawl Meta Knight who was overloaded with power.
If character design is discussed, "bad design" should not be thrown around just because a character is bad, too good, has too many weaknesses, has too many strengths, etc. Take Bowser; yes, he has problems landing, dealing with... I don't know, Bowser problems, but what is Bowser? That takes some studying and yes, people don't have all the time or desire to study even one character, but Bowser's pretty much a Zangief, a heavyweight grappler. Characters like that will have problems in neutral and disadvantage, by make up by having an insane advantage. Is that really bad? No, conceptually, it's fine, but execution? Smash 4 Bowser is probably the most well-executed and it shows even if it had to take some patches. Now, for the game itself, so game concept, mechanics, and the other characters, and how Bowser interacts with it, well, that's a bit tough since I don't know Bowser.
I know everyone here loves to use
as the poster child of bad design, and I agree that his design is horrible. But if I had to pick the hands down most poorly, utterly **** designed character in the entire game, or possibly even the entire series, I'd have to go with
. As polarizing as Lucario is, at least he has a gameplan. At least he is somewhat viable. At least he doesn't have an objectively superior counterpart in the roster that outclasses him in every way. Falco is the epitome of **** tier design and if I made a tier list for character designs, he'd be right in the bottom of the barrel. This guy...has absolutely no gameplan. His moves don't flow together and don't combo into each other in any meaningful ways. His mobility is slow for absolutely no reason, and he's not even compensated for being a snail whatsoever. I've never gotten into the starfox franchise myself, but I'm doubtful that his design has any relevance to a pilot in an on-rails sci-fi shooter either. It's almost disgustingly obvious how Falco was designed. The devs made Fox (and to be fair, they did an excellent job with him). Then, they looked at Fox's tools and said, "let's just make Falco have opposing strengths." So they took Fox, butchered his ground speed, butchered his autocancel aerials, neutered up smash, and compensated for all of this by giving him a higher jumps and some hitstun on his lasers. Then they made him blue, birdlike, and named him Falco.
For the most part, his moves flow; he is after all, based on, in my opinion, one of the most well-designed characters in Smash. The problem is the developers making extremely poor decisions regarding some of his moves that made him overwhelming to the cast (Edit
which had the consequence of giving him bad history. Falco is supposed to be a Guile, a zoner with good, close-range normals, but not really good jump-ins or approach normals rather than the SNK-esque boss or "do everything, kill everything", flames Iori Yagami.
Falco's concept is fine, but the execution is not. The TLDR version is that he's supposed to be Luigi with a longer ranged (and good) projectile, but in practice he's a worse Ryu in almost every aspect.
I still have no idea where the hell this comparison comes from or why people believe it. It's like saying, hypothetically, a butchered Guile is supposed to be Ken. I'm sorry, but what? Falco is defensive; he has no jump-ins and no and shouldn't have any approach tools, but the developers screwed up with Melee and Brawl Falco making it seem like Falco's supposed to be a SFV Nash or a Ken. Anyway, he's supposed to make you feel like you have to approach allowing him to make use of his normals to setup in any way he can; versatile normals like Guile and of course, like Fox. Luigi is more offensive; he can pressure by going in and using his normals, has some jump-ins, and can try to zone or challenge zoning, but prefers to be in with more "linear" setups; tons of bread and butters that do their job.
I swear if it's just because they combo... Really, people? Really? At this rate, we might as well say Zelda is an inferior Marth because her tippers aren't as versatile. Oh, wait, they're entirely different characters.