You guys missed what I said entirely. I still don't think BD would be more unique than Magolor. And I don't think it's because I'm biased towards him.
The fact that Zelda and Robin (and Ness and Lucas, if you wanna count them) use forms of magic doesn't downgrade Magolor's potential. Zelda has a unique projectile, being able to challenge from a distance, has a reflector that can be used to rapidly wrack up damage, and has a teleportation spell with massive knockback. This gives her potential to fight from any distance, though primarily long range. I'd say she's best at dishing out chunks of damage at a range, making her best at chipping. Robin has a chargeable projectile with multiple stages, each stage having multiple unique applications. A fire spell to disrupt movement. A wind spell to attack effectively from above and spike. But each spell has limited uses, making Robin ineffective at chipping. But unlike Zelda, he's not incompetent up-close. All these qualities make him a strategic zoner.
The above arguments prove one important thing: Robin and Zelda have drastically different playstyles. The possibilities of what can be done with Magic users are endless. Traditional melee weapons are much more limited, however.
The reason I don't believe BD has potential to be unique is because what a spear is at the core is a melee weapon with unparalleled range. There's not a whole lot they can do with that. We already have a ton of ranged melee weapon users, with one more underway via DLC. Link fills the role of destructive and versatile, being able to adapt to many different playstyles, whether it be power-housing, chipping, or a combination of both. Marth fills the role of spacer with his tipper mechanic, forcing players to mind their distance if they want to play him effectively. Meta Knight fills the role of rush-down close-combatant. In Brawl, he filled the role of undefeatable, with his combination of speed, priority, and strength. If BD were to be included, Meta Knight would be the one out of the bunch he's be least like. Lastly, Ike fills the role of ranged power-house.
As you can see, there's not a whole lot of spaces for Bandana Dee to fill. He certainly has potential to have a unique moveset, but most of the balance contribution he would give would be shared with Ike, Marth, and Link. I suppose the only way to save him from the gutter are the specials. But if you make them center on spear tossing, or using various gadgets the Waddle Dees have used throughout the generations, you have a smaller, lighter, less powerful Link with a bit more range. If you give him the tipper, which would be completely pointless given the spear's nature as a thrusting weapon, he would be be a smaller, lighter, less powerful Marth who would most likely have a few projectiles. He might be able to be pulled off then. I don't think he would work as a powerhouse or even a glass cannon, so that's pretty much out of the question.
This isn't to crush your hopes for his inclusion though; he could still be pulled off. Sakuri has exceeded our expectations before. The only way I think Bandana Dee could be reasonable to include is if Sakuri goes and gives him some unexpected but reasonably creative quirk with his specials. But I really can't see that happening. Sorry, deeple.
Magolor, on the other hand, has so much potential within reason. His playstyle could be that of an annoying trickster, which would be absolutely perfect. For his up special, he could have some kind of mirror move which teleports him upwards. (or wherever you tilt the stick) If someone else is close by on the other side of the mirror, they could switch places with him. I can see Robin using Elwind offstage, and then Mags using his up special after Robin becomes helpless, sending Mags back to the stage, and Robin to his doom. His neutral special could be where he creates a black hole that sucks players towards it. He could compliment this by having smash attacks that work most effectively the closer you are to him, making the black hole the start of a deadly finisher combo. On top of that, it could suck in projectiles to grow in size and range. His down special could be a simple mirror or portal based reflector that deals damage similarly to Nayru's Love. A counter could work good, too. Lastly, his side special could be a teleportation move on the lines of Shadow Sneak or Dimensional Cape, but would have the movement range of Din's Fire. These, and the close range smash quirk would make Magolor an epic counter to most projectile-centric character's and rush-down character's. That is the kind of balance contribution I honestly, as someone who plays For Glory a lot, think the game would benefit from.