Mario is the biggest series for Nintendo, and it didn't get a new rep in Brawl. Zelda might not get a new rep this time. DK is bigger than Kirby and at this point it'd be lucky to get Dixie as a clone. Just because a series is big doesn't mean it'll get a rep, especially when it has its main cast already covered. Look at Mario last time. Bandana Dee is a b-tier character from a series that both has its principal cast already and just received two original characters last time. Being next in line doesn't really mean much when it's basically the biggest thing the character has in it's favour (considering there's a big drop-off in the series between the existing three and BD); Bandana Dee support only really took off because people needed a Kirby character to support. And it's not Mario, Kirby's not going to start reaching into the next tier for original candidates.
To put it in another light, if MK or Dedede hadn't been included in Brawl, the support for Bandana Dee this time around would be practically non-existent, all the support would go to one of them. Sure BD might have the potential for originality, but in a series like Kirby... there doesn't need to be a designated spot for "new Kirby rep", and in all likelihood there isn't.
I don't really have anything else to say about BD, and I won't go on past this, because this is the place to support Bandana Dee, not decry him, but it's surprising to me how many people have been duped into thinking he is anything more than a very dark horse with a very outside shot at best.