The major appeal for Bandana Waddle Dee is twofold:
Much like noctowlite said, Bandana Dee is quickly becoming the fourth main character of the Kirby series. After coming back in Super Star Ultra for the Revenge of the King subgame after his minor appearance in the original’s Megaton Punch game, he then returned in Return to Dream Land as the fourth playable character and has been a staple character since. He had a minor role in Triple Deluxe, and he was the secondary protagonist in Kirby & the Rainbow Curse, and it looks like he isn’t going anywhere.
His spear-based gameplay would be quite unique. You could use his play style from Return to Dream Land as at least some basis. I envision Bandana Dee as a character that, while small, has impressive reach and disjointed hitboxes thanks to his spear, but he needs a few frames to wind up some of his hits. He could also throw the spear for a projectile, spin the spear to form a propeller much like in Return to Dream Land...honestly, I feel like he’d play a lot differently than Meta Knight due to the range of his attacks alone. You wouldn’t rush down with Bananda Dee, you’d play more of a mid range spacing game.
As for other Kirby reps, Adeleine would be interesting, though perhaps best as an assist trophy. Maybe Sakurai can finally include elements from games that came after Super Star, or stuff from the Dark Matter games...I think Kirby’s Final Smash is the only thing.
